TYP: pandas/core/dtypes/base.py

pandas/core/dtypes/base.py

@@ -1,12 +1,15 @@
 """Extend pandas with custom array types"""
-from typing import Any, List, Optional, Tuple, Type
+from typing import TYPE_CHECKING, Any, List, Optional, Tuple, Type
 
 import numpy as np
 
 from pandas.errors import AbstractMethodError
 
 from pandas.core.dtypes.generic import ABCDataFrame, ABCIndexClass, ABCSeries
 
+if TYPE_CHECKING:
+    from pandas.core.arrays import ExtensionArray  # noqa: F401
+
 
 class ExtensionDtype:
     """
@@ -26,7 +29,6 @@ class ExtensionDtype:
 
     * type
     * name
-    * construct_from_string
 
     The following attributes influence the behavior of the dtype in
     pandas operations
@@ -71,7 +73,7 @@ class property**.
         class ExtensionDtype:
 
             def __from_arrow__(
-                self, array: pyarrow.Array/ChunkedArray
+                self, array: Union[pyarrow.Array, pyarrow.ChunkedArray]
             ) -> ExtensionArray:
                 ...
 
@@ -119,11 +121,11 @@ def __eq__(self, other: Any) -> bool:
     def __hash__(self) -> int:
         return hash(tuple(getattr(self, attr) for attr in self._metadata))
 
-    def __ne__(self, other) -> bool:
+    def __ne__(self, other: Any) -> bool:
         return not self.__eq__(other)
 
     @property
-    def na_value(self):
+    def na_value(self) -> object:
         """
         Default NA value to use for this type.
 
@@ -181,7 +183,7 @@ def names(self) -> Optional[List[str]]:
         return None
 
     @classmethod
-    def construct_array_type(cls):
+    def construct_array_type(cls) -> Type["ExtensionArray"]:
         """
         Return the array type associated with this dtype.
 
@@ -246,7 +248,7 @@ def construct_from_string(cls, string: str):
         return cls()
 
     @classmethod
-    def is_dtype(cls, dtype) -> bool:
+    def is_dtype(cls, dtype: object) -> bool:
         """
         Check if we match 'dtype'.
 
@@ -257,7 +259,7 @@ def is_dtype(cls, dtype) -> bool:
 
         Returns
         -------
-        is_dtype : bool
+        bool
 
         Notes
         -----

pandas/core/dtypes/dtypes.py

@@ -74,7 +74,7 @@ def register(self, dtype: Type[ExtensionDtype]) -> None:
 
     def find(
         self, dtype: Union[Type[ExtensionDtype], str]
-    ) -> Optional[Type[ExtensionDtype]]:
+    ) -> Optional[Union[ExtensionDtype, Type[ExtensionDtype]]]:
         """
         Parameters
         ----------