Check for object dtype
Check for object dtype

Line 1072-1075: Earlier the code was explicitly checking for datatype to not be None, fixed the problem as advised by @taldcroft(Github).
Line 1091 - Indentation error was being indicated in the docstring, fixed.

astropy/astropy,larrybradley/astropy,mhvk/astropy,larrybradley/astropy,pllim/astropy,astropy/astropy,mhvk/astropy,mhvk/astropy,mhvk/astropy,astropy/astropy,lpsinger/astropy,astropy/astropy,mhvk/astropy,pllim/astropy,pllim/astropy,lpsinger/astropy,lpsinger/astropy,larrybradley/astropy,larrybradley/astropy,astropy/astropy,pllim/astropy,pllim/astropy,lpsinger/astropy,larrybradley/astropy,lpsinger/astropy