docs: def _find_max_beta_token_len():
      """
      Finds the maximum length of a single betacode token.
  
      Returns:
      The length of the longest key in the betacode map, which corresponds to the
      longest single betacode token.
      """
      max_beta_len = -1
      for beta, uni in _map.BETACODE_MAP.items():
          if len(beta) > max_beta_len:
              max_beta_len = len(beta)
  
      return max_beta_len