code: def rewrite(self, block_address, new_bytes):
          
          if not self.is_tag_set_auth():
              return True
  
          error = self.do_auth(block_address)
          if not error:
              (error, data) = self.rfid.read(block_address)
              if not error:
                  for i in range(len(new_bytes)):
                      if new_bytes[i] != None:
                          if self.debug:
                              print("Changing pos " + str(i) + " with current value " + str(data[i]) + " to " + str(new_bytes[i]))
  
                          data[i] = new_bytes[i]
  
                  error = self.rfid.write(block_address, data)
                  if self.debug:
                      print("Writing " + str(data) + " to " + self.sector_string(block_address))
  
          return error
docs: Rewrites block with new bytes, keeping the old ones if None is passed. Tag and auth must be set - does auth.
          Returns error state.