CLN: Improve typing

Fix many mypy issues
Use Label

Author: bashtage

pandas/core/frame.py

@@ -9,8 +9,8 @@
 labeling information
 """
 import collections
-import datetime
 from collections import abc
+import datetime
 from io import StringIO
 import itertools
 import sys
@@ -40,7 +40,7 @@
 from pandas._config import get_option
 
 from pandas._libs import algos as libalgos, lib
-from pandas._typing import Axes, Axis, Dtype, FilePathOrBuffer, Level, Renamer
+from pandas._typing import Axes, Axis, Dtype, FilePathOrBuffer, Label, Level, Renamer
 from pandas.compat import PY37
 from pandas.compat._optional import import_optional_dependency
 from pandas.compat.numpy import function as nv
@@ -1854,14 +1854,14 @@ def _from_arrays(cls, arrays, columns, index, dtype=None) -> "DataFrame":
     def to_stata(
         self,
         path: FilePathOrBuffer,
-        convert_dates: Optional[Dict[Hashable, str]] = None,
+        convert_dates: Optional[Dict[Label, str]] = None,
         write_index: bool = True,
         byteorder: Optional[str] = None,
         time_stamp: Optional[datetime.datetime] = None,
         data_label: Optional[str] = None,
-        variable_labels: Optional[Dict[Hashable, str]] = None,
+        variable_labels: Optional[Dict[Label, str]] = None,
         version: Optional[int] = 114,
-        convert_strl: Optional[Sequence[Hashable]] = None,
+        convert_strl: Optional[Sequence[Label]] = None,
     ) -> None:
         """
         Export DataFrame object to Stata dta format.