docs: def afw_json_importer(input_file: str) -> dict:
      """ Imports a AFW from a JSON file.
  
      :param str input_file: path+filename to input JSON file;
      :return: *(dict)* representing a AFW.
      """
      file = open(input_file)
      json_file = json.load(file)
  
      transitions = {}  # key [state in states, action in alphabet]
      #  value [string representing boolean expression]
      for p in json_file['transitions']:
          transitions[p[0], p[1]] = p[2]
  
      # return map
      afw = {
          'alphabet': set(json_file['alphabet']),
          'states': set(json_file['states']),
          'initial_state': json_file['initial_state'],
          'accepting_states': set(json_file['accepting_states']),
          'transitions': transitions
      }
      return afw