'mod_fullname doubles as the name of the VARIABLE holding our new sh
context.  for example:
derp = sh()
from derp import ls
here, mod_fullname will be "derp".  keep that in mind as we go throug
the rest of this function'

def find_module(self, mod_fullname, path=None):

    parent_frame = inspect.currentframe().f_back
    while in_importlib(parent_frame):
        parent_frame = parent_frame.f_back
    module = fetch_module_from_frame(mod_fullname, parent_frame)
    if (not module):
        return None
    if (module.__class__.__name__ not in self.restrict_to):
        return None
    return self
