code: def _build_hash_secret(self, seq_seed, seq_len=HASH_SECRET_LENGTH,
              mod_value=HASH_SECRET_MOD_CONST):
          
  
          # make sure we use a list, tuples are immutable
          fbn_seq = list(seq_seed)
          for i in range(seq_len):
              fbn_seq.append(fbn_seq[-1] + fbn_seq[-2])
          hash_secret = list(map(
              lambda c: chr(c % mod_value + self.HASH_SECRET_CHAR_OFFSET),
              fbn_seq[2:]))
          return ''.join(hash_secret)
docs: Build a seed for the hash based on the Fibonacci sequence
  
          Take first `seq_len` + len(`seq_seed`) characters of Fibonacci
          sequence, starting with `seq_seed`, and applying e % `mod_value` +
          `HASH_SECRET_CHAR_OFFSET` to the resulting sequence, then return as
          a string
  
          @param tuple|list seq_seed
          @param int seq_len
          @param int mod_value
          @return str