pf not found

[rabi01]

I installed PYPOWER along with numpy and scipy using pip install, and after that I tried running pf -h and I got the error
Traceback (most recent call last):
File "<pyshell#18>", line 1, in
pf -h
NameError: name 'pf' is not defined.

Even I tried to used runpf(ppe) by loading the case9 into ppe, and I got the error.
My code
from pypower.api import case9, ppoption,runpf,printpf
ppc = case9()
#ppopt = ppoption(PF_ALG=2)
r = runpf(ppc)
printpf(r)

error:
Traceback (most recent call last):
File "C:\Python27\test.py", line 4, in
r = runpf(ppc)
File "C:\Python27-64\lib\site-packages\pypower\runpf.py", line 95, in runpf
ppc = ext2int(ppc)
File "C:\Python27-64\lib\site-packages\pypower\ext2int.py", line 152, in ext2int
o["bus"]["e2i"] = zeros(max(o["bus"]["i2e"]) + 1)
TypeError: 'numpy.float64' object cannot be interpreted as an index.

Please help. Thanks in advance