Issue with WCS.wcs.cunit equality

[astrofrog]

The WCS.wcs.cunit attribute uses a class called UnitListProxy - and it seems that class doesn't correctly define __eq__:

In [47]: wcs = WCS(naxis=2)

In [48]: wcs.wcs.cunit = ['deg', 'm/s']

In [49]: wcs.wcs.cunit == wcs.wcs.cunit
Out[49]: False

I think this should be treated as a bug.

[geekypathak21]

@astrofrog I want to resolve this bug but I can't able to find definition of class UnitListProxy can you please give some elaboration about this class

[astrofrog]

@himanshupathak21061998 - the class is defined in https://github.com/astropy/astropy/blob/master/astropy/wcs/src/unit_list_proxy.c (it's written in C)