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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 _expand_space(self):
 """ Creates an internal list where the variables with dimensionality larger than one are expanded. This list is the one that is used internally to do the optimization. """


        ## --- Expand the config space
        self._expand_config_space()

        ## --- Expand the space
        self.space_expanded = []
        for variable in self.space:
            self.space_expanded += variable.expand()