NameError: Case mismatch for module name sys

[Martin Erren]

Hello,

in a package named "Sys" (not of my own). I need:

import traceback, sys

Then I get

"NameError: Case mismatch for module name sys"
(filename lib\Sys\Sys.py)

I don't need "Sys" in the package,
but "sys" in the python-standard lib.

Is the namespace case-insensitive, but I have to address
it case-sensitive?

Can I "leave" the package-Directory in imports explicitely?

Thanks in advance:

Martin Erren