BUG in read_pickle (#48007)

* fix: read_pickle notes on backward compatibility

* updated: flake8 error handling

* updated: removed trailing whitespace

* updated: trim whitespace

Author: Kinza-Raza

pandas/io/pickle.py

@@ -160,11 +160,14 @@ def read_pickle(
 
     Notes
     -----
-    read_pickle is only guaranteed to be backwards compatible to pandas 0.20.3.
+    read_pickle is only guaranteed to be backwards compatible to pandas 0.20.3
+    provided the object was serialized with to_pickle.
 
     Examples
     --------
-    >>> original_df = pd.DataFrame({{"foo": range(5), "bar": range(5, 10)}})  # doctest: +SKIP
+    >>> original_df = pd.DataFrame(
+    ...     {{"foo": range(5), "bar": range(5, 10)}}
+    ...    )  # doctest: +SKIP
     >>> original_df  # doctest: +SKIP
        foo  bar
     0    0    5
@@ -182,7 +185,7 @@ def read_pickle(
     2    2    7
     3    3    8
     4    4    9
-    """  # noqa: E501
+    """
     excs_to_catch = (AttributeError, ImportError, ModuleNotFoundError, TypeError)
     with get_handle(
         filepath_or_buffer,