code: def __str__(self) -> str:
      return f"({', '.join([str(i) for i in self.inputs])} -- {', '.join([str(i) for i in self.outputs])})"
  
imports: from dataclasses import dataclass, field
  import lexer
  import parser
  from typing import Optional
label_desc: Use image node_id 1 for calling the StackEffect obj's underlying member method code with example usage: obj.__str__() and returns: str, str, str, str, str