CLN: Add annotations for stata

Add type annotations in Stata
General clean up
Fix one small bug using in rather than ==

pandas/core/frame.py

@@ -9,6 +9,7 @@
 labeling information
 """
 import collections
+import datetime
 from collections import abc
 from io import StringIO
 import itertools
@@ -18,6 +19,7 @@
     IO,
     TYPE_CHECKING,
     Any,
+    Dict,
     FrozenSet,
     Hashable,
     Iterable,
@@ -1851,16 +1853,16 @@ def _from_arrays(cls, arrays, columns, index, dtype=None) -> "DataFrame":
     @deprecate_kwarg(old_arg_name="fname", new_arg_name="path")
     def to_stata(
         self,
-        path,
-        convert_dates=None,
-        write_index=True,
-        byteorder=None,
-        time_stamp=None,
-        data_label=None,
-        variable_labels=None,
-        version=114,
-        convert_strl=None,
-    ):
+        path: FilePathOrBuffer,
+        convert_dates: Optional[Dict[Hashable, 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,
+        version: Optional[int] = 114,
+        convert_strl: Optional[Sequence[Hashable]] = None,
+    ) -> None:
         """
         Export DataFrame object to Stata dta format.
 

pandas/io/common.py

@@ -160,10 +160,9 @@ def get_filepath_or_buffer(
 
     Returns
     -------
-    tuple of ({a filepath_ or buffer or S3File instance},
-              encoding, str,
-              compression, str,
-              should_close, bool)
+    Tuple[FilePathOrBuffer, str, str, bool]
+        Tuple containing the filepath or buffer, the encoding, the compression
+        and should_close.
     """
     filepath_or_buffer = stringify_path(filepath_or_buffer)