add code and sample test
- [ ] closes #xxxx (Replace xxxx with the Github issue number)
- [ ] [Tests added and passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#writing-tests) if fixing a bug or adding a new feature
- [ ] All [code checks passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit).
- [ ] Added an entry in the latest `doc/source/whatsnew/vX.X.X.rst` file if fixing a bug or adding a new feature.

Hello @pranavc28! 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/core/reshape/merge.py`](https://github.com/pandas-dev/pandas/blob/0c644fdcff746042db02cfc534bb726ddffdf3c3/pandas/core/reshape/merge.py):

> [Line 2170:9](https://github.com/pandas-dev/pandas/blob/0c644fdcff746042db02cfc534bb726ddffdf3c3/pandas/core/reshape/merge.py#L2170): [E128](https://duckduckgo.com/?q=pep8%20E128) continuation line under-indented for visual indent
> [Line 2171:13](https://github.com/pandas-dev/pandas/blob/0c644fdcff746042db02cfc534bb726ddffdf3c3/pandas/core/reshape/merge.py#L2171): [E128](https://duckduckgo.com/?q=pep8%20E128) continuation line under-indented for visual indent
> [Line 2171:15](https://github.com/pandas-dev/pandas/blob/0c644fdcff746042db02cfc534bb726ddffdf3c3/pandas/core/reshape/merge.py#L2171): [E251](https://duckduckgo.com/?q=pep8%20E251) unexpected spaces around keyword / parameter equals
> [Line 2171:17](https://github.com/pandas-dev/pandas/blob/0c644fdcff746042db02cfc534bb726ddffdf3c3/pandas/core/reshape/merge.py#L2171): [E251](https://duckduckgo.com/?q=pep8%20E251) unexpected spaces around keyword / parameter equals
> [Line 2172:15](https://github.com/pandas-dev/pandas/blob/0c644fdcff746042db02cfc534bb726ddffdf3c3/pandas/core/reshape/merge.py#L2172): [E251](https://duckduckgo.com/?q=pep8%20E251) unexpected spaces around keyword / parameter equals
> [Line 2172:17](https://github.com/pandas-dev/pandas/blob/0c644fdcff746042db02cfc534bb726ddffdf3c3/pandas/core/reshape/merge.py#L2172): [E251](https://duckduckgo.com/?q=pep8%20E251) unexpected spaces around keyword / parameter equals

* In the file [`test_merge_dtype.py`](https://github.com/pandas-dev/pandas/blob/0c644fdcff746042db02cfc534bb726ddffdf3c3/test_merge_dtype.py):

> [Line 4:1](https://github.com/pandas-dev/pandas/blob/0c644fdcff746042db02cfc534bb726ddffdf3c3/test_merge_dtype.py#L4): [E302](https://duckduckgo.com/?q=pep8%20E302) expected 2 blank lines, found 1
> [Line 22:1](https://github.com/pandas-dev/pandas/blob/0c644fdcff746042db02cfc534bb726ddffdf3c3/test_merge_dtype.py#L22): [E302](https://duckduckgo.com/?q=pep8%20E302) expected 2 blank lines, found 1
> [Line 40:1](https://github.com/pandas-dev/pandas/blob/0c644fdcff746042db02cfc534bb726ddffdf3c3/test_merge_dtype.py#L40): [E302](https://duckduckgo.com/?q=pep8%20E302) expected 2 blank lines, found 1

 which issue does this fix? This pull request is stale because it has been open for thirty days with no activity. Please [update](https://pandas.pydata.org/pandas-docs/stable/development/contributing.html#updating-your-pull-request) and respond to this comment if you're still interested in working on this. Thanks for the pull request, but it's unclear what this addresses. If interested in continuing, please provide more information, address the review and we can reopen 