class_docstr: Sort the frames which satisfy the condition
  
  Arguments:
      node (AbstractPlan): The OrderBy Plan
code: def _extract_column_name(self, col):
      col_name = []
      if isinstance(col, TupleValueExpression):
          col_name += [col.col_alias]
      elif isinstance(col, FunctionExpression):
          col_name += col.col_alias
      else:
          raise ExecutorError(
              "Expression type {} is not supported.".format(type(col))
          )
      return col_name
  
file_path: evadb/evadb/executor/orderby_executor.py
imports: from typing import Iterator
  from evadb.database import EvaDBDatabase
  from evadb.executor.abstract_executor import AbstractExecutor
  from evadb.executor.executor_utils import ExecutorError
  from evadb.expression.function_expression import FunctionExpression
  from evadb.expression.tuple_value_expression import TupleValueExpression
  from evadb.models.storage.batch import Batch
  from evadb.parser.types import ParserOrderBySortType
  from evadb.plan_nodes.orderby_plan import OrderByPlan
label_desc: Use image node_id 2 for calling the OrderByExecutor obj's underlying member method code with example usage: obj._extract_column_name(col) and returns: col_name