diff --git a/py7zr/py7zr.py b/py7zr/py7zr.py
index 6b2db64a..938e14c7 100644
--- a/py7zr/py7zr.py
+++ b/py7zr/py7zr.py
@@ -370,7 +370,10 @@ def _real_get_contents(self, password) -> None:
             packinfo = self.header.main_streams.packinfo
             packsizes = packinfo.packsizes
             subinfo = self.header.main_streams.substreamsinfo
-            unpacksizes = subinfo.unpacksizes if subinfo is not None and subinfo.unpacksizes is not None else [x.unpacksizes[-1] for x in folders]
+            if subinfo is not None and subinfo.unpacksizes is not None:
+                unpacksizes = subinfo.unpacksizes
+            else:
+                unpacksizes = [x.unpacksizes[-1] for x in folders]
         else:
             subinfo = None
             folders = None