diff --git a/mdutils/fileutils/fileutils.py b/mdutils/fileutils/fileutils.py
index 787786f..cacdab4 100644
--- a/mdutils/fileutils/fileutils.py
+++ b/mdutils/fileutils/fileutils.py
@@ -5,7 +5,7 @@
 # This file is part of mdutils. https://github.com/didix21/mdutils
 #
 # MIT License: (C) 2018 Dídac Coll
-
+from typing import Optional
 
 class MarkDownFile(object):
     """MarkDownFile class creates a new file of MarkDown extension.
@@ -15,7 +15,7 @@ class MarkDownFile(object):
         - Rewrite a file with new data.
         - Write at the end of the file."""
 
-    def __init__(self, name='', dirname: str = None):
+    def __init__(self, name='', dirname: Optional[str] = None):
         """Creates a markdown file, if name is not empty.
         :param str name: provide the file name or a path joinly with the file name. For example: `./my-path/my-file.md`.
         :param str dirname: use dirname if you want to provide the path separately from the name. 
@@ -26,27 +26,27 @@ def __init__(self, name='', dirname: str = None):
             self.file = open(f'{self.file_name}', 'w+', encoding='UTF-8')
             self.file.close()
 
-    def _get_file_name(self, name: str, dirname: str = None ) -> str:
+    def _get_file_name(self, name: str, dirname: Optional[str] = None ) -> str:
             if dirname:
                 return f'{dirname}/{name}' if name.endswith('.md') else f'{dirname}/{name}.md'
             
             return name if name.endswith('.md') else f'{name}.md'
 
-    def rewrite_all_file(self, data):
+    def rewrite_all_file(self, data: str):
         """Rewrite all the data of a Markdown file by ``data``.
 
         :param str data: is a string containing all the data that is written in the markdown file."""
         with open(f'{self.file_name}', 'w', encoding='utf-8') as self.file:
             self.file.write(data)
 
-    def append_end(self, data):
+    def append_end(self, data: str):
         """Write at the last position of a Markdown file.
 
         :param str data: is a string containing all the data that is written in the markdown file."""
         with open(f'{self.file_name}', 'a', encoding='utf-8') as self.file:
             self.file.write(data)
 
-    def append_after_second_line(self, data):
+    def append_after_second_line(self, data: str):
         """Write after the file's first line.
 
         :param str data: is a string containing all the data that is written in the markdown file."""
diff --git a/mdutils/mdutils.py b/mdutils/mdutils.py
index 86e4f0c..bce3f17 100644
--- a/mdutils/mdutils.py
+++ b/mdutils/mdutils.py
@@ -27,6 +27,7 @@
 from mdutils.tools.TextUtils import TextUtils
 from mdutils.tools.MDList import MDList, MDCheckbox
 from textwrap import fill
+from typing import Union, Optional, List
 
 
 class MdUtils:
@@ -44,7 +45,7 @@ class MdUtils:
     - **file_data_text:** contains all the file data that will be written on the markdown file.
     """
 
-    def __init__(self, file_name, title="", author=""):
+    def __init__(self, file_name: str, title: str = '', author: str = ''):
         """
 
         :param file_name: it is the name of the Markdown file.
@@ -65,7 +66,7 @@ def __init__(self, file_name, title="", author=""):
         self.reference = Reference()
         self.image = Image(reference=self.reference)
 
-    def create_md_file(self):
+    def create_md_file(self) -> MarkDownFile:
         """It creates a new Markdown file.
         :return: return an instance of a MarkDownFile."""
         md_file = MarkDownFile(self.file_name)
@@ -80,7 +81,7 @@ def get_md_text(self) -> str:
         :return: return a string with the markdown text."""
         return self.title + self.table_of_contents + self.file_data_text + self.reference.get_references_as_markdown()
 
-    def read_md_file(self, file_name):
+    def read_md_file(self, file_name: str) -> str:
         """Reads a Markdown file and save it to global class `file_data_text`.
 
         :param file_name: Markdown file's name that has to be read.
@@ -93,7 +94,7 @@ def read_md_file(self, file_name):
 
         return file_data
 
-    def new_header(self, level, title, style='atx', add_table_of_contents='y', header_id=''):
+    def new_header(self, level: int, title: str, style: str = 'atx', add_table_of_contents: str = 'y', header_id: str = '') -> str:
         """Add a new header to the Markdown file.
 
         :param level: Header level. *atx* style can take values 1 til 6 and *setext* style take values 1 and 2.
@@ -122,7 +123,7 @@ def new_header(self, level, title, style='atx', add_table_of_contents='y', heade
         self.___update_file_data(self.header.choose_header(level, title, style, header_id))
         return self.header.choose_header(level, title, style, header_id)
 
-    def __add_new_item_table_of_content(self, level, item):
+    def __add_new_item_table_of_content(self, level: int, item: Union[List[str], str]):
         """Automatically add new atx headers to the table of contents.
 
         :param level: add levels up to 6.
@@ -143,7 +144,7 @@ def __add_new_item_table_of_content(self, level, item):
             curr.append([])
 
 
-    def new_table_of_contents(self, table_title="Table of contents", depth=1, marker=''):
+    def new_table_of_contents(self, table_title: str = "Table of contents", depth: int = 1, marker: str = '') -> str:
         """Table of contents can be created if Headers of 'atx' style have been defined.
 
         This method allows to create a table of contents and define a title for it. Moreover, `depth` allows user to
@@ -175,7 +176,7 @@ def new_table_of_contents(self, table_title="Table of contents", depth=1, marker
 
         return self.table_of_contents + marker_table_of_contents
 
-    def new_table(self, columns, rows, text, text_align='center', marker=''):
+    def new_table(self, columns: int, rows: int, text: List[str], text_align: str = 'center', marker: str = '') -> str:
         """This method takes a list of strings and creates a table.
 
             Using arguments ``columns`` and ``rows`` allows to create a table of *n* columns and *m* rows. The
@@ -222,7 +223,7 @@ def new_table(self, columns, rows, text, text_align='center', marker=''):
 
         return text_table
 
-    def new_paragraph(self, text='', bold_italics_code='', color='black', align='', wrap_width=0):
+    def new_paragraph(self, text: str = '', bold_italics_code: str = '', color: str = 'black', align: str = '', wrap_width:int = 0) -> str:
         """Add a new paragraph to Markdown file. The text is saved to the global variable file_data_text.
 
         :param text: is a string containing the paragraph text. Optionally, the paragraph text is returned.
@@ -252,7 +253,7 @@ def new_paragraph(self, text='', bold_italics_code='', color='black', align='',
 
         return self.file_data_text
 
-    def new_line(self, text='', bold_italics_code='', color='black', align='', wrap_width=0):
+    def new_line(self, text: str = '', bold_italics_code: str = '', color: str = 'black', align: str = '', wrap_width: int = 0) -> str:
         """Add a new line to Markdown file. The text is saved to the global variable file_data_text.
 
         :param text: is a string containing the paragraph text. Optionally, the paragraph text is returned.
@@ -281,7 +282,7 @@ def new_line(self, text='', bold_italics_code='', color='black', align='', wrap_
 
         return self.file_data_text
 
-    def write(self, text='', bold_italics_code='', color='black', align='', marker='', wrap_width=0):
+    def write(self, text: str = '', bold_italics_code: str = '', color: str = 'black', align: str = '', marker: str = '', wrap_width: int = 0) -> str:
         """Write text in ``file_Data_text`` string.
 
         :param text: a text a string.
@@ -314,7 +315,7 @@ def write(self, text='', bold_italics_code='', color='black', align='', marker='
 
         return new_text
 
-    def insert_code(self, code, language=''):
+    def insert_code(self, code: str, language: str = '') -> str:
         """This method allows to insert a peace of code on a markdown file.
 
         :param code: code string.
@@ -328,7 +329,7 @@ def insert_code(self, code, language=''):
         self.___update_file_data(md_code)
         return md_code
 
-    def create_marker(self, text_marker):
+    def create_marker(self, text_marker: str) -> str:
         """This will add a marker to ``file_data_text`` and returns the marker result in order to be used whenever
             you need.
 
@@ -345,7 +346,7 @@ def create_marker(self, text_marker):
         self.___update_file_data(new_marker)
         return new_marker
 
-    def place_text_using_marker(self, text, marker):
+    def place_text_using_marker(self, text: str, marker: str) -> str:
         """It replace a previous marker created with ``create_marker`` with a text string.
 
             This method is going to search for the ``marker`` argument, which has been created previously using
@@ -363,7 +364,7 @@ def place_text_using_marker(self, text, marker):
     def ___update_file_data(self, file_data):
         self.file_data_text += file_data
 
-    def new_inline_link(self, link, text=None, bold_italics_code='', align=''):
+    def new_inline_link(self, link: str, text: Optional[str] = None, bold_italics_code: str = '', align: str = '') -> str:
         """Creates a inline link in markdown format.
 
         :param link:
@@ -392,7 +393,7 @@ def new_inline_link(self, link, text=None, bold_italics_code='', align=''):
 
         return Inline.new_link(link=link, text=n_text)
 
-    def new_reference_link(self, link, text, reference_tag=None, bold_italics_code='', align=''):
+    def new_reference_link(self, link: str, text: str, reference_tag: Optional[str] = None, bold_italics_code: str = '', align: str = '') -> str:
         """Creates a reference link in markdown format. All references will be stored at the end of the markdown file.
 
 
@@ -444,7 +445,7 @@ def new_reference_link(self, link, text, reference_tag=None, bold_italics_code='
         return self.reference.new_link(link=link, text=n_text, reference_tag=reference_tag)
 
     @staticmethod
-    def new_inline_image(text, path):
+    def new_inline_image(text: str, path: str) -> str:
         """Add inline images in a markdown file. For example ``[MyImage](../MyImage.jpg)``.
 
         :param text: Text that is going to be displayed in the markdown file as a iamge.
@@ -458,7 +459,7 @@ def new_inline_image(text, path):
 
         return Image.new_inline_image(text=text, path=path)
 
-    def new_reference_image(self, text, path, reference_tag=None):
+    def new_reference_image(self, text: str, path: str, reference_tag: Optional[str] = None) -> str:
         """Add reference images in a markdown file. For example ``[MyImage][my_image]``. All references will be stored
         at the end of the markdown file.
 
@@ -476,7 +477,7 @@ def new_reference_image(self, text, path, reference_tag=None):
         """
         return self.image.new_reference_image(text=text, path=path, reference_tag=reference_tag)
 
-    def new_list(self, items: [str], marked_with: str = "-"):
+    def new_list(self, items: List[str], marked_with: str = "-"):
         """Add unordered or ordered list in MarkDown file.
 
         :param items: Array of items for generating the list.
@@ -489,7 +490,7 @@ def new_list(self, items: [str], marked_with: str = "-"):
         mdlist = MDList(items, marked_with)
         self.___update_file_data('\n' + mdlist.get_md())
 
-    def new_checkbox_list(self, items: [str], checked: bool = False):
+    def new_checkbox_list(self, items: List[str], checked: bool = False):
         """Add checkbox list in MarkDown file.
 
         :param items: Array of items for generating the checkbox list.
diff --git a/mdutils/tools/Header.py b/mdutils/tools/Header.py
index 2afbddc..ae04e69 100644
--- a/mdutils/tools/Header.py
+++ b/mdutils/tools/Header.py
@@ -25,7 +25,7 @@ class Header:
     # *                             Atx-Style                            *
     # ********************************************************************
     @staticmethod
-    def atx_level_1(title, header_id=''):
+    def atx_level_1(title: str, header_id: str = '') -> str:
         """Return a atx level 1 header.
 
         :param str title: text title.
@@ -39,7 +39,7 @@ def atx_level_1(title, header_id=''):
         return '\n# ' + title + header_id + '\n'
 
     @staticmethod
-    def atx_level_2(title, header_id=''):
+    def atx_level_2(title: str, header_id: str = '') -> str:
         """Return a atx level 2 header.
 
         :param str title: text title.
@@ -53,7 +53,7 @@ def atx_level_2(title, header_id=''):
         return '\n## ' + title + header_id + '\n'
 
     @staticmethod
-    def atx_level_3(title, header_id=''):
+    def atx_level_3(title: str, header_id: str = '') -> str:
         """Return a atx level 3 header.
 
         :param str title: text title.
@@ -67,7 +67,7 @@ def atx_level_3(title, header_id=''):
         return '\n### ' + title + header_id + '\n'
 
     @staticmethod
-    def atx_level_4(title, header_id=''):
+    def atx_level_4(title: str, header_id: str = '') -> str:
         """Return a atx level 4 header.
 
         :param str title: text title.
@@ -81,7 +81,7 @@ def atx_level_4(title, header_id=''):
         return '\n#### ' + title + header_id + '\n'
 
     @staticmethod
-    def atx_level_5(title, header_id=''):
+    def atx_level_5(title: str, header_id: str = '') -> str:
         """Return a atx level 5 header.
 
         :param str title: text title.
@@ -95,7 +95,7 @@ def atx_level_5(title, header_id=''):
         return '\n##### ' + title + header_id + '\n'
 
     @staticmethod
-    def atx_level_6(title, header_id=''):
+    def atx_level_6(title: str, header_id: str = '') -> str:
         """Return a atx level 6 header.
 
         :param str title: text title.
@@ -112,7 +112,7 @@ def atx_level_6(title, header_id=''):
     # *                          Setext-Style                            *
     # ********************************************************************
     @staticmethod
-    def setext_level_1(title):
+    def setext_level_1(title: str) -> str:
         """Return a setext level 1 header.
 
         :param str title: text title.
@@ -123,7 +123,7 @@ def setext_level_1(title):
         return '\n' + title + '\n' + ''.join(['=' for _ in title]) + '\n'
 
     @staticmethod
-    def setext_level_2(title):
+    def setext_level_2(title: str) -> str:
         """Return a setext level 1 header.
 
                 :param str title: text title.
@@ -134,7 +134,7 @@ def setext_level_2(title):
         return '\n' + title + '\n' + ''.join(['-' for _ in title]) + '\n'
 
     @staticmethod
-    def header_anchor(text, link=""):
+    def header_anchor(text: str, link: str = '') -> str:
         """Creates an internal link of a defined Header level 1 or level 2 in the markdown file.
 
         Giving a text string an text link you can create an internal link of already existing header. If the ``link``
@@ -160,7 +160,7 @@ def header_anchor(text, link=""):
         return '[' + text + '](' + link + ')'
 
     @staticmethod
-    def choose_header(level, title, style='atx', header_id=''):
+    def choose_header(level: int, title: str, style: str = 'atx', header_id: str = '') -> str:
         # noinspection SpellCheckingInspection
         """This method choose the style and the header level.
 
diff --git a/mdutils/tools/Image.py b/mdutils/tools/Image.py
index f8a03ef..8e96bf5 100644
--- a/mdutils/tools/Image.py
+++ b/mdutils/tools/Image.py
@@ -11,7 +11,7 @@
 
 class Image:
 
-    def __init__(self, reference):
+    def __init__(self, reference: Reference):
         """
         :param reference:
         :type reference: Reference
@@ -19,7 +19,7 @@ def __init__(self, reference):
         self.reference = reference
 
     @staticmethod
-    def new_inline_image(text, path, tooltip=None):
+    def new_inline_image(text: str, path: str, tooltip: str = None) -> str:
         """
         :param text: Text that is going to be displayed in the markdown file as a iamge.
         :type text: str
@@ -32,7 +32,7 @@ def new_inline_image(text, path, tooltip=None):
         """
         return '!' + Inline.new_link(link=path, text=text, tooltip=tooltip)
 
-    def new_reference_image(self, text, path, reference_tag=None, tooltip=None):
+    def new_reference_image(self, text: str, path: str, reference_tag: str = None, tooltip: str = None) -> str:
         """
         :param text: Text that is going to be displayed in the markdown file as a image.
         :type text: str
diff --git a/mdutils/tools/Link.py b/mdutils/tools/Link.py
index ebdbae0..6db35bb 100644
--- a/mdutils/tools/Link.py
+++ b/mdutils/tools/Link.py
@@ -13,27 +13,27 @@ class Reference:
     def __init__(self):
         self.references = {}
 
-    def get_references(self):
+    def get_references(self) -> dict:
         """
         :return:
         :rtype: dict
         """
         return self.references
 
-    def get_references_as_markdown(self):
+    def get_references_as_markdown(self) -> str:
         """
         :return:
         :rtype: str
         """
         if not bool(self.references):
-            return ""
+            return ''
 
-        references_as_markdown = ""
+        references_as_markdown = ''
         for key in sorted(self.references.keys()):
             references_as_markdown += '[' + key + ']: ' + self.references[key] + '\n'
         return '\n\n\n' + references_as_markdown
 
-    def new_link(self, link, text, reference_tag=None, tooltip=None):
+    def new_link(self, link: str, text: str, reference_tag: str = None, tooltip: str = None) -> str:
         """
         :param link:
         :type link: str
@@ -53,7 +53,7 @@ def new_link(self, link, text, reference_tag=None, tooltip=None):
         self.__update_ref(link, reference_tag, tooltip)
         return '[' + text + '][' + reference_tag + ']'
 
-    def __update_ref(self, link, reference_tag, tooltip=None):
+    def __update_ref(self, link: str, reference_tag: str, tooltip: str = None):
         if not (reference_tag in self.references.keys()):
             if tooltip is not None:
                 self.references.update({reference_tag: TextUtils.add_tooltip(link, tooltip)})
@@ -65,7 +65,7 @@ def __update_ref(self, link, reference_tag, tooltip=None):
 class Inline:
 
     @staticmethod
-    def new_link(link, text=None, tooltip=None):
+    def new_link(link: str, text: str = None, tooltip: str = None):
         """
         :param link:
         :type link: str
@@ -89,7 +89,7 @@ def new_link(link, text=None, tooltip=None):
         return Inline.__md_link(link=link, text=text)
 
     @staticmethod
-    def __md_link(link, text):
+    def __md_link(link: str, text: str):
         return TextUtils.text_external_link(text, link)
 
 
diff --git a/mdutils/tools/MDList.py b/mdutils/tools/MDList.py
index 941bbc3..87d0a49 100644
--- a/mdutils/tools/MDList.py
+++ b/mdutils/tools/MDList.py
@@ -5,6 +5,7 @@
 # This file is part of mdutils. https://github.com/didix21/mdutils
 #
 # MIT License: (C) 2020 Dídac Coll
+from typing import List
 import re
 
 
@@ -12,7 +13,7 @@ class MDListHelper:
     def __init__(self):
         self.n_tabs = 0
 
-    def _get_unordered_markdown_list(self, items: [str], marker: str) -> str:
+    def _get_unordered_markdown_list(self, items, marker: str) -> str:
         md_list = ""
         for item in items:
             if isinstance(item, list):
@@ -24,7 +25,7 @@ def _get_unordered_markdown_list(self, items: [str], marker: str) -> str:
 
         return md_list
 
-    def _get_ordered_markdown_list(self, items: [str]) -> str:
+    def _get_ordered_markdown_list(self, items) -> str:
         md_list = ""
         n_marker = 1
         for item in items:
@@ -60,7 +61,7 @@ class MDList(MDListHelper):
     """This class allows to create unordered or ordered MarkDown list.
 
     """
-    def __init__(self, items: [str], marked_with: str = '-'):
+    def __init__(self, items, marked_with: str = '-'):
         """
 
         :param items: Array of items for generating the list.
@@ -87,7 +88,7 @@ class MDCheckbox(MDListHelper):
 
     """
 
-    def __init__(self, items: [str], checked: bool = False):
+    def __init__(self, items, checked: bool = False):
         """
 
         :param items: Array of items for generating the list.
diff --git a/mdutils/tools/Table.py b/mdutils/tools/Table.py
index fcdcf6b..b51694b 100644
--- a/mdutils/tools/Table.py
+++ b/mdutils/tools/Table.py
@@ -5,7 +5,7 @@
 # This file is part of mdutils. https://github.com/didix21/mdutils
 #
 # MIT License: (C) 2020 Dídac Coll
-from typing import Optional, Union, Iterable
+from typing import Optional, Union, Iterable, List
 
 
 class Table:
@@ -69,7 +69,7 @@ def _align(columns: int, text_align: Optional[Union[str, Iterable]] = None) -> s
 
         return column_align_string
 
-    def create_table(self, columns: int, rows: int, text: [str], text_align: Optional[Union[str, list]] = None):
+    def create_table(self, columns: int, rows: int, text: List[str], text_align: Optional[Union[str, list]] = None):
         """This method takes a list of strings and creates a table.
 
             Using arguments ``columns`` and ``rows`` allows to create a table of *n* columns and *m* rows.
diff --git a/mdutils/tools/TableOfContents.py b/mdutils/tools/TableOfContents.py
index 6f1adae..f432edc 100644
--- a/mdutils/tools/TableOfContents.py
+++ b/mdutils/tools/TableOfContents.py
@@ -5,11 +5,12 @@
 # This file is part of mdutils. https://github.com/didix21/mdutils
 #
 # MIT License: (C) 2020 Dídac Coll
+from typing import List
 import re
 
 
 class TableOfContents:
-    def _loop_through(self, elements, tab='', depth=1):
+    def _loop_through(self, elements, tab: str = '', depth: int = 1) -> str:
         """Method that go through a list of elements that contain strings and other list and return a string.
 
         The returned string is ready to be written in a markdown file in order to create a table of contents.
@@ -22,7 +23,7 @@ def _loop_through(self, elements, tab='', depth=1):
         :type depth: int
         :rtype: str
         """
-        elements_to_string = ""
+        elements_to_string = ''
         for item in elements:
             if isinstance(item, list):
                 if item and depth > 1:
@@ -33,7 +34,7 @@ def _loop_through(self, elements, tab='', depth=1):
 
         return elements_to_string
 
-    def create_table_of_contents(self, array_of_title_contents, depth=1):
+    def create_table_of_contents(self, array_of_title_contents: List[str], depth: int = 1) -> str:
         """This method can create a table of contents using an array of the different titles. The depth can be changed.
         :param array_of_title_contents: a string list with the different headers.
         :type array_of_title_contents: list
@@ -43,7 +44,7 @@ def create_table_of_contents(self, array_of_title_contents, depth=1):
         :rtype: str
         """
         if depth in range(1,7):
-            table_of_contents = ""
+            table_of_contents = ''
             table_of_contents += self._loop_through(array_of_title_contents, depth=depth)
             table_of_contents += '\n'
             return table_of_contents
diff --git a/mdutils/tools/TextUtils.py b/mdutils/tools/TextUtils.py
index 3afa7e0..4ee603c 100644
--- a/mdutils/tools/TextUtils.py
+++ b/mdutils/tools/TextUtils.py
@@ -13,7 +13,7 @@ class TextUtils:
     """
 
     @staticmethod
-    def bold(text):
+    def bold(text: str) -> str:
         """Bold text converter.
 
         :param text: a text string.
@@ -23,7 +23,7 @@ def bold(text):
         return '**' + text + '**'
 
     @staticmethod
-    def italics(text):
+    def italics(text: str) -> str:
         """Italics text converter.
 
         :param text: a text string.
@@ -33,7 +33,7 @@ def italics(text):
         return '*' + text + '*'
 
     @staticmethod
-    def inline_code(text):
+    def inline_code(text: str) -> str:
         """Inline code text converter.
 
         :param text: a text string.
@@ -43,7 +43,7 @@ def inline_code(text):
         return '``' + text + '``'
 
     @staticmethod
-    def center_text(text):
+    def center_text(text: str) -> str:
         """Place a text string to center.
 
         :param text: a text string.
@@ -53,7 +53,7 @@ def center_text(text):
         return '<center>' + text + '</center>'
 
     @staticmethod
-    def text_color(text, color="black"):
+    def text_color(text: str, color: str = "black") -> str:
         """Change text color.
 
         :param text: it is the text that will be changed its color.
@@ -67,7 +67,7 @@ def text_color(text, color="black"):
         return '<font color="' + color + '">' + text + '</font>'
 
     @staticmethod
-    def text_external_link(text, link=''):
+    def text_external_link(text: str, link: str = '') -> str:
         """ Using this method can be created an external link of a file or a web page.
 
         :param text: Text to be displayed.
@@ -80,7 +80,7 @@ def text_external_link(text, link=''):
         return '[' + text + '](' + link + ')'
 
     @staticmethod
-    def insert_code(code, language=''):
+    def insert_code(code: str, language: str = '') -> str:
         """This method allows to insert a peace of code.
 
         :param code: code string.
@@ -96,7 +96,7 @@ def insert_code(code, language=''):
             return '```' + language + '\n' + code + '\n```'
 
     @staticmethod
-    def text_format(text, bold_italics_code='', color='black', align=''):
+    def text_format(text: str, bold_italics_code: str = '', color: str = 'black', align: str = '') -> str:
         """Text format helps to write multiple text format such as bold, italics and color.
 
         :param text: it is a string in which will be added the mew format
@@ -142,7 +142,7 @@ def text_format(text, bold_italics_code='', color='black', align=''):
         return new_text_format
 
     @staticmethod
-    def add_tooltip(link, tip):
+    def add_tooltip(link: str, tip: str) -> str:
         """
         :param link:
         :type link: str