Looking around, I may have misled you. The types are in numeric types, so do
```
from . import numerictypes as nt
```
 then you can do 
```
if issubclass(dtype.type, nt.complexfloating):
    blah
```
etc. You can see examples in `numpy/core/arrayprint.py`. The `issubdtype` function is in there also.

But now I'm wondering why these functions are in `_methods.py` since they aren't  array methods or called from c code.