diff --git a/pytest_abra/custom_fixtures.py b/pytest_abra/custom_fixtures.py
index d627812..c5e8b6c 100644
--- a/pytest_abra/custom_fixtures.py
+++ b/pytest_abra/custom_fixtures.py
@@ -93,7 +93,7 @@ def URL(env_config: dict[str, str]) -> BaseUrl:
 
 
 @pytest.fixture(scope="session")
-def imap_client() -> None:
+def imap_client() -> Generator[Imbox]:
     """imap email client using credentials from environment variables"""
 
     assert os.environ["IMAP_HOST"]