Checks if `phi_variable` is a phi variable, and if it contains `variable` as a sub-variable.

        :param phi_variable:
        :param variable:
        :return:

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