code: def encode_hex(self, hex_str):
          
          numbers = (int('1' + hex_str[i:i+12], 16)
                     for i in range(0, len(hex_str), 12))
          try:
              return self.encode(*numbers)
          except ValueError:
              return ''
docs: Converts a hexadecimal string (e.g. a MongoDB id) to a hashid.
  
          :param hex_str The hexadecimal string to encodes
  
          >>> Hashids.encode_hex('507f1f77bcf86cd799439011')
          'y42LW46J9luq3Xq9XMly'