ENH: Deprecate non-keyword arguments for Resampler.interpolate
- [x] xref #41485
- [x] tests added / passed
- [x] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing.html#code-standards) for how to run them
- [x] whatsnew entry

Hello @Anupam-USP! Thanks for updating this PR. We checked the lines you've touched for [PEP 8](https://www.python.org/dev/peps/pep-0008) issues, and found:





There are currently no PEP 8 issues detected in this Pull Request. Cheers! :beers: 

##### Comment last updated at 2021-06-04 16:15:25 UTC > I'll review later, but note that this should be `Resampler.interpolate`, not `DataFrame.interpolate` - [example usage](https://stackoverflow.com/q/47148446/4451315)

I have tried but this pre-commit test is not passing by any means. What should I do for passing it? > > I'll review later, but note that this should be `Resampler.interpolate`, not `DataFrame.interpolate` - [example usage](https://stackoverflow.com/q/47148446/4451315)
> 
> I have tried but this pre-commit test is not passing by any means. What should I do for passing it?

see https://pandas.pydata.org/pandas-docs/stable/development/contributing.html#pre-commit I always fail some cases, no matter what I do. Pasting the check's error is also not giving satisfactory results. What should I do to pass them all? @Anupam-USP if you can rebase & update I am not able to get rid of this issue `AssertionError: Did not see expected warning of class 'FutureWarning'` when I am using `with tm.assert_produces_warning`. Sorry I tried! > I am not able to get rid of this issue `AssertionError: Did not see expected warning of class 'FutureWarning'` when I am using `with tm.assert_produces_warning`. Sorry I tried!

What happens if you remove the `tm.assert_produces_warning` line and run the test? Can you show your complete output? ![image](https://user-images.githubusercontent.com/56446640/120444568-5cddec00-c3a5-11eb-9520-cc1ad1f6d3bb.png)
![image](https://user-images.githubusercontent.com/56446640/120444707-8139c880-c3a5-11eb-9235-10dc73b0409f.png)

This happens when i insert the test, otherwise checks are getting passed without it >  otherwise checks are getting passed without it

Do they still pass if you also change
```
result = s.resample("3s").interpolate("linear")
```
to
```
result = s.resample("3s").interpolate("linear", 0)
```
?
(you're deprecating `axis` as positional, but not `method`). Then, this should raise some warning

----

If you want, let's continue this discussion on gitter https://gitter.im/pydata/pandas  No means when I am removing it, I am not getting any error. It comes only after inserting it So, without the `tm.asssert_produces_warning` line, and with
```
result = s.resample("3s").interpolate("linear", 0)
```
instead of
```
result = s.resample("3s").interpolate("linear")
```
, it passes? OK, I'll take a look on Friday Yes it got passed. Thank you, but I wanted to know how? And it isn't mentioned anywhere clearly?  Thanks @Anupam-USP 