minor point: `np.int32` values are not instances of python `int`:

```
In [3]: isinstance(int64(), int)
Out[3]: True

In [4]: isinstance(int32(), int)
Out[4]: False
```

however .. this is probably so rare that it doesn't really matter

i suppose the "correct" way would be this:

```
In [10]: import numbers

In [11]: import numpy as np

In [12]: isinstance(1, (numbers.Integral, np.integer))
Out[12]: True

In [13]: isinstance(int32(), (numbers.Integral, np.integer))
Out[13]: True
```

but that seems *so* overkill, up to u really ...