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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 pop_configuration(self):
 """ Pushes the currently active configuration from the stack of configurations managed by this mapping. :raises IndexError: If there is only one configuration in the stack. """

        if len(self.__configurations) == 1:
            raise IndexError('Can not pop the last configuration from the '
                             'stack of configurations.')
        self.__configurations.pop()
        self.__mapped_attr_cache.clear()