code: def mifare_classic_read_block(self, block_number):
          
          # Send InDataExchange request to read block of MiFare data.
          response = self.call_function(PN532_COMMAND_INDATAEXCHANGE,
                                        params=[0x01, MIFARE_CMD_READ, block_number & 0xFF],
                                        response_length=17)
          # Check first response is 0x00 to show success.
          if response[0] != 0x00:
              return None
          # Return first 4 bytes since 16 bytes are always returned.
          return response[1:]
docs: Read a block of data from the card.  Block number should be the block
          to read.  If the block is successfully read a bytearray of length 16 with
          data starting at the specified block will be returned.  If the block is
          not read then None will be returned.