Add session attribute to Group/User/Page/Thread

tests/test_page.py

@@ -2,7 +2,7 @@ import fbchat
 from fbchat._page import Page
 
 
-def test_page_from_graphql():
+def test_page_from_graphql(session):
     data = {
         "id": "123456",
         "name": "Some school",
@@ -12,10 +12,11 @@ def test_page_from_graphql():
         "city": None,
     }
     assert Page(
+        session=session,
         id="123456",
         photo=fbchat.Image(url="https://scontent-arn2-1.xx.fbcdn.net/v/..."),
         name="Some school",
         url="https://www.facebook.com/some-school/",
         city=None,
         category="SCHOOL",
-    ) == Page._from_graphql(data)
+    ) == Page._from_graphql(session, data)