code: def char(self, label):
      s = self.new_state()
      e = self.new_state()
      nfa = NFA(s)
      nfa.add_transition(s, label, e)
      nfa.add_final_state(e)
      return nfa
  
file_path: whoosh/src/whoosh/automata/reg.py
imports: from whoosh.automata.fsa import ANY, EPSILON, NFA
label_desc: Use image node_id 4 for calling the RegexBuilder obj's underlying member method code with example usage: obj.char(label) and returns: nfa