The Python X Library is intended to be a fully functional X client
library for Python programs. It is written entirely in Python, in
contrast to earlier X libraries for Python which were interfaces to
the C Xlib.

This is possible to do since X client programs communicate with the X
server via the X protocol. The communication takes place over TCP/IP,
Unix sockets, DECnet or any other streaming network protocol. The C
Xlib is merely an interface to this protocol, providing functions
suitable for a C environment.
