1 files changed, 2 insertions, 0 deletions

diff --git a/libmat2/archive.py b/libmat2/archive.py
index 29db417..cfc9671 100644
--- a/libmat2/archive.py
+++ b/libmat2/archive.py
@@ -438,9 +438,11 @@ class ZipParser(ArchiveBasedAbstractParser):
 
     @staticmethod
     def _get_member_compression(member: ArchiveMember):
+        assert isinstance(member, zipfile.ZipInfo)  # please mypy
         return member.compress_type
 
     @staticmethod
     def _set_member_compression(member: ArchiveMember, compression) -> ArchiveMember:
+        assert isinstance(member, zipfile.ZipInfo)  # please mypy
         member.compress_type = compression
         return member