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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 remove(cls, module_name):
 """ drop a previously created guard on ``module_name`` if the module is not guarded, then this is a no-op. """

        module_guards = cls._guards.get(module_name, False)
        if module_guards:
            module_guards.pop()
            cls._num_entries -= 1
            if cls._num_entries < 1:
                if cls._num_entries < 0:
                    raise Exception(
                        'Bug: ImportGuardHook._num_entries became negative!'
                    )
                cls._uninstall()