code: def __str__(self) -> str:
      if self.do_unnest:
          return f"unnest({self._func_expr})"
      return f"{self._func_expr}"
  
imports: from __future__ import annotations
  from typing import Union
  from evadb.expression.abstract_expression import AbstractExpression
  from evadb.expression.function_expression import FunctionExpression
  from evadb.parser.alias import Alias
  from evadb.parser.select_statement import SelectStatement
  from evadb.parser.types import JoinType
label_desc: Use image node_id 4 for calling the TableValuedExpression obj's underlying member method code with example usage: obj.__str__() and returns: self, str, self, str