docs: def copy(self, src, chunk_size=None, progress_callback=None):
          """Copy data from another file instance.
  
          :param src: Source stream.
          :param chunk_size: Chunk size to read from source stream.
          """
          fp = src.open(mode='rb')
          try:
              return self.save(
                  fp, chunk_size=chunk_size, progress_callback=progress_callback)
          finally:
              fp.close()