CLN: Cleanup ops.py
- [x] tests added / passed
- [x] passes `git diff upstream/master | flake8 --diff`

Cleanup duplicated code paths before fixing some ops related issues.

## [Current coverage](https://codecov.io/gh/pydata/pandas/pull/13605?src=pr) is **84.33%**

> Merging [#13605](https://codecov.io/gh/pydata/pandas/pull/13605?src=pr) into [master](https://codecov.io/gh/pydata/pandas/branch/master?src=pr) will decrease coverage by **<.01%**

``` diff
@@             master     #13605   diff @@
==========================================
  Files           138        138          
  Lines         51100      51092     -8   
  Methods           0          0          
  Messages          0          0          
  Branches          0          0          
==========================================
- Hits          43097      43090     -7   
+ Misses         8003       8002     -1   
  Partials          0          0          
```

> Powered by [Codecov](https://codecov.io?src=pr). Last updated by [5605f99...729997b](https://codecov.io/gh/pydata/pandas/compare/5605f99105b6a97fb950fbebbf83d2cac0b23ef1...729997b93ded983ccbdcbb1d7c57d00c0c89fe21?src=pr)
 Looks good! Small comment
 thxs!
