Schemas can be bools too in newer drafts.

jsonschema/protocols.py

@@ -5,7 +5,7 @@
 # for reference material on Protocols, see
 # https://www.python.org/dev/peps/pep-0544/
 
-from typing import Any, ClassVar, Iterator, Optional
+from typing import Any, ClassVar, Iterator, Optional, Union
 
 try:
  from typing import Protocol, runtime_checkable
@@ -36,7 +36,7 @@ class Validator(Protocol):
  """
  The protocol to which all validator classes should adhere.
 
- :argument dict schema: the schema that the validator object
+ :argument schema: the schema that the validator object
  will validate with. It is assumed to be valid, and providing
  an invalid schema can lead to undefined behavior. See
  `Validator.check_schema` to validate a schema first.
@@ -66,11 +66,11 @@ class Validator(Protocol):
  TYPE_CHECKER: ClassVar[TypeChecker]
 
  #: The schema that was passed in when initializing the object.
- schema: dict
+ schema: Union[dict, bool]
 
  def __init__(
  self,
- schema: dict,
+ schema: Union[dict, bool],
  resolver: Optional[RefResolver] = None,
  format_checker: Optional[FormatChecker] = None,
  ) -> None: