diff --git a/metaflow/includefile.py b/metaflow/includefile.py
index 33f4529bec..569f028e43 100644
--- a/metaflow/includefile.py
+++ b/metaflow/includefile.py
@@ -227,6 +227,10 @@ def __init__(self, is_text, encoding):
         self._encoding = encoding
 
     def convert(self, value, param, ctx):
+        if callable(value):
+            # Already a correct type
+            return value
+
         value = os.path.expanduser(value)
         ok, file_type, err = LocalFile.is_file_handled(value)
         if not ok:
diff --git a/metaflow/parameters.py b/metaflow/parameters.py
index f07590e453..9ee37809ef 100644
--- a/metaflow/parameters.py
+++ b/metaflow/parameters.py
@@ -36,6 +36,9 @@ class JSONTypeClass(click.ParamType):
     name = 'JSON'
 
     def convert(self, value, param, ctx):
+        if not isinstance(value, strtype):
+            # Already a correct type
+            return value
         try:
             return json.loads(value)
         except: