fix
Hello @Nikoleta-v3! Thanks for submitting the PR.

 - There are no PEP8 issues in the file [`pandas/core/dtypes/cast.py`](https://github.com/Nikoleta-v3/pandas/blob/89e58cbefa6b4b44eb7712fbc7d1405969e9dcec/pandas/core/dtypes/cast.py) !

 - There are no PEP8 issues in the file [`pandas/core/dtypes/common.py`](https://github.com/Nikoleta-v3/pandas/blob/89e58cbefa6b4b44eb7712fbc7d1405969e9dcec/pandas/core/dtypes/common.py) !

 - In the file [`pandas/tests/series/test_constructors.py`](https://github.com/Nikoleta-v3/pandas/blob/89e58cbefa6b4b44eb7712fbc7d1405969e9dcec/pandas/tests/series/test_constructors.py), following                are the PEP8 issues :
> [Line 152:1](https://github.com/Nikoleta-v3/pandas/blob/89e58cbefa6b4b44eb7712fbc7d1405969e9dcec/pandas/tests/series/test_constructors.py#L152): [W293](https://duckduckgo.com/?q=pep8%20W293) blank line contains whitespace


