Added context manager

cas_wrapper.py

@@ -30,6 +30,18 @@ class CasWrapper:
             self._cas = local['cas']
             self._cas['login']()
 
+    def __enter__(self):
+        with local.env(
+            CAS_API_KEY=self._cas_api_key,
+            SIGNER_ID=self._cas_signer_id,
+        ):
+            self._cas = local['cas']
+            self._cas['login']()
+        return self
+
+    def __exit__(self, exc_type, value, traceback):
+        self._cas['logout']()
+
     def notarize(
             self,
             local_path: str,