code: def module_sys_modules_key(key):
      
      moduleparts = key.split(".")
      for partnum, part in enumerate(moduleparts):
          modkey = ".".join(moduleparts[partnum:])
          if modkey in sys.modules:
              return modkey
      return None
docs: Check if a module is in the sys.modules dictionary in some manner.  If so,
      return the key used in that dictionary.
  
      :param key: our key to the module.
      :returns: the key in sys.modules or None.