Looking for a graph (as in network, nodes) package

[John Henry]

I am looking for a ready made simple graph package.  I found an
extensive one in the piana package but when  I try to use just the
graph portion, it fails to load because of the line:

class Graph(object):
 ...

It seems that their Graph is subclassed from "object" but I couldn't
find a "object" class anywhere.  So, I abandoned using that one.

Before I reinvent the wheel and start writing one myself, can somebody
point me to a ready made one?  I am afraid Googling "Python Graph"
wouldn't be much help (millions and trillions of hits).

Thanks,