class_docstr: An abstract class for the executor engine
  Arguments:
      node (AbstractPlan): Plan node corresponding to this executor
class_docstr_tok: ["An","abstract","class","for","the","executor","engine","Arguments",":","node","(","AbstractPlan",")",":","Plan","node","corresponding","to","this","executor"]
docstr: appends a child executor node
  
  Arguments:
      child {AbstractExecutor} -- child node
docstr_tok: ["appends","a","child","executor","node","Arguments",":","child","{","AbstractExecutor","}","--","child","node"]
code: def append_child(self, child: AbstractExecutor):
      """
      appends a child executor node
  
      Arguments:
          child {AbstractExecutor} -- child node
      """
      self._children.append(child)
  
file_path: evadb/evadb/executor/abstract_executor.py
imports: from abc import ABC, abstractmethod
  from collections import deque
  from typing import TYPE_CHECKING, Any, Generator, Iterable, List, TypeVar
  from evadb.database import EvaDBDatabase
  from evadb.models.storage.batch import Batch
  from evadb.plan_nodes.abstract_plan import AbstractPlan
label_desc: Use image node_id 3 for calling the AbstractExecutor obj's underlying member method code with example usage: obj.append_child(child) without return types