numpy.nper() with pmt=0 gives unexpected "divide by zero" warning

[OlehOnyshchak]

Reproducing code example:

import numpy as np

np.nper(rate=0.1, pmt=0, pv=-500, fv=1500)

Error message:

numpy\lib\financial.py:308: RuntimeWarning: divide by zero encountered in long_scalars
A = -(fv + pv)/(pmt+0)

Actual Result:

np.nper() returns the correct result with "divide by zero" warning

Expected Result:

np.nper() returns the same correct result but without warning

Numpy/Python version information:

1.16.4 3.6.5 |Anaconda, Inc.| (default, Mar 29 2018, 13:32:41) [MSC v.1900 64 bit (AMD64)]