Installing frappe-bench

I was installing ERPNext on a VM using the guide line provided and I upgraded pip to 19.1.1 and I run

pip install frappe-bench

and i get an error

Traceback (most recent call last):
File “/usr/local/bin/pip”, line 7, in <module
from pip import main
ImportError: cannot import name main

Can any one help me on how to fix it?
Thank you

Which guide did you use ? IIRC hitchhiker guide mentions that this pip method is broken.