Clone a module and make changes to the copy

To phrase another way, can I inherit from a module, and then override or modify parts of it?

Yes.

import module

You can use stuff from module or override stuff in your script.

You can also do this to create a "derived" module.

Call this "module_2".

from module import *

Which imports everything. You can then use stuff from module or override stuff in this new module, "module_2".

Other scripts can then do

import module_2

And get all the stuff from module modified by the overrides in module_2.

The namespace of a Python module is writable. Consider:

# contrived.pyCONST = 100def foo():    return CONST

You can modify the value of CONST after it's been imported:

import contrivedcontrived.CONST = 200contrived.foo() # 200

However, only a single instance of a module can be imported so there is not anyway to create a clone and continue to use the original module. If you don't need access to the original module, then it's fairly straight-forward to create a wrapper module and override whatever you want to change.

One thing to look out for is that code like this will not work as you expect:

# clone.pyfrom contrived import *CONST = 200

This will actually assign CONST in clone's namespace, functions imported from contrived will continue to reference the CONST in contrive's namespace:

import cloneclone.foo() # 100

In this case you could do something like this:

# clone.pyimport contrivedcontrived.CONST = 200from contrived import *