@@ -314,7 +314,7 @@ def _count_blocks(obj):
block_truncate = block.truncate
block_getvalue = block.getvalue
- for c in chain(*obj.as_raw_chunks()):
+ for c in chain.from_iterable(obj.as_raw_chunks()):
c = c.to_bytes(1, 'big')
block_write(c)
n += 1