code: def add_data(self, data):
          
  
          if self.data_size - self.data_index < len(data):
              return Error.DESTINATION_BUFFER_TOO_SMALL
  
          if self.in_progress is not None:
              self.in_progress.data += data
  
          return Error.NO_ERROR
docs: Add data to the currently in progress entry.
  
          Args:
              data (bytes): The data that we want to add.
  
          Returns:
              int: An error code