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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 child_class(self, child):
 """ Return the class a child element should be an instance of :param child: The name of the child element :return: The class """

        for prop, klassdef in self.c_children.values():
            if child == prop:
                if isinstance(klassdef, list):
                    return klassdef[0]
                else:
                    return klassdef
        return None