code: def add_arc(self, next_, nonterminal_or_string=None):
      assert nonterminal_or_string is None or isinstance(
          nonterminal_or_string, str
      )
      assert isinstance(next_, NFAState)
      self.arcs.append(NFAArc(next_, nonterminal_or_string))
  
imports: from typing import Optional, Iterator, Tuple, List
  from parso.python.tokenize import tokenize
  from parso.utils import parse_version_string
  from parso.python.token import PythonTokenTypes
label_desc: Use image node_id 2 for calling the NFAState obj's underlying member method code with example usage: obj.add_arc(next_, nonterminal_or_string) without return types