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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def module_sys_modules_key(key):
 """ 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. """

    moduleparts = key.split(".")
    for partnum, part in enumerate(moduleparts):
        modkey = ".".join(moduleparts[partnum:])
        if modkey in sys.modules:
            return modkey
    return None