docs: def p_instance_list(self, p):
          '''instance_list : instance_list domain_section
                           | instance_list nonfluents_section
                           | instance_list objects_section
                           | instance_list init_state_section
                           | instance_list max_nondef_actions_section
                           | instance_list horizon_spec_section
                           | instance_list discount_section
                           | empty'''
          if p[1] is None:
              p[0] = dict()
          else:
              name, section = p[2]
              p[1][name] = section
              p[0] = p[1]