code: def _get_hash(self, file_obj):
          
          size = 0
          hash_buider = self.hash_builder()
          for piece in self._get_file_iterator(file_obj):
              hash_buider.update(piece)
              size += len(piece)
  
          file_obj.seek(0)
  
          return "%s_%x" % (hash_buider.hexdigest(), size)
docs: Compute hash for the `file_obj`.
  
          Attr:
              file_obj (obj): File-like object with ``.write()`` and ``.seek()``.
  
          Returns:
              str: Hexdigest of the hash.