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