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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 _phi_node_contains(self, phi_variable, variable):
 """ Checks if `phi_variable` is a phi variable, and if it contains `variable` as a sub-variable. :param phi_variable: :param variable: :return: """


        if self.variable_manager[self.function.addr].is_phi_variable(phi_variable):
            return variable in self.variable_manager[self.function.addr].get_phi_subvariables(phi_variable)
        return False