String whitespace
Added a function that would remove whitespaces
Hello @minnaau! Thanks for opening this PR. We checked the lines you've touched for [PEP 8](https://www.python.org/dev/peps/pep-0008) issues, and found:

* In the file [`pandas/tests/strings/test_split_partition.py`](https://github.com/pandas-dev/pandas/blob/d429458c61a1e82392549fff1a14bf003dae2250/pandas/tests/strings/test_split_partition.py):

> [Line 111:1](https://github.com/pandas-dev/pandas/blob/d429458c61a1e82392549fff1a14bf003dae2250/pandas/tests/strings/test_split_partition.py#L111): [E302](https://duckduckgo.com/?q=pep8%20E302) expected 2 blank lines, found 1
> [Line 126:1](https://github.com/pandas-dev/pandas/blob/d429458c61a1e82392549fff1a14bf003dae2250/pandas/tests/strings/test_split_partition.py#L126): [W293](https://duckduckgo.com/?q=pep8%20W293) blank line contains whitespace
> [Line 131:1](https://github.com/pandas-dev/pandas/blob/d429458c61a1e82392549fff1a14bf003dae2250/pandas/tests/strings/test_split_partition.py#L131): [W293](https://duckduckgo.com/?q=pep8%20W293) blank line contains whitespace
> [Line 132:25](https://github.com/pandas-dev/pandas/blob/d429458c61a1e82392549fff1a14bf003dae2250/pandas/tests/strings/test_split_partition.py#L132): [W291](https://duckduckgo.com/?q=pep8%20W291) trailing whitespace
> [Line 136:1](https://github.com/pandas-dev/pandas/blob/d429458c61a1e82392549fff1a14bf003dae2250/pandas/tests/strings/test_split_partition.py#L136): [W293](https://duckduckgo.com/?q=pep8%20W293) blank line contains whitespace
> [Line 141:1](https://github.com/pandas-dev/pandas/blob/d429458c61a1e82392549fff1a14bf003dae2250/pandas/tests/strings/test_split_partition.py#L141): [W293](https://duckduckgo.com/?q=pep8%20W293) blank line contains whitespace
> [Line 146:1](https://github.com/pandas-dev/pandas/blob/d429458c61a1e82392549fff1a14bf003dae2250/pandas/tests/strings/test_split_partition.py#L146): [W293](https://duckduckgo.com/?q=pep8%20W293) blank line contains whitespace

 Please open only on pr for the same change