Import Literal from typing_extensions instead

We can't import it from typing until Py3.8.

synapse/events/presence_router.py

@@ -13,7 +13,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from typing import TYPE_CHECKING, Dict, Iterable, Literal, Set, Union
+from typing import TYPE_CHECKING, Dict, Iterable, Set, Union
+
+from typing_extensions import Literal
 
 from synapse.handlers.presence import UserPresenceState
 

synapse/handlers/presence.py

@@ -31,15 +31,14 @@
     FrozenSet,
     Iterable,
     List,
-    Literal,
     Optional,
     Set,
     Tuple,
     Union,
 )
 
 from prometheus_client import Counter
-from typing_extensions import ContextManager
+from typing_extensions import ContextManager, Literal
 
 import synapse.metrics
 from synapse.api.constants import EventTypes, Membership, PresenceState

tests/events/test_presence_router.py

@@ -12,9 +12,10 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from typing import Dict, Iterable, List, Literal, Optional, Set, Union
+from typing import Dict, Iterable, List, Optional, Set, Union
 
 import attr
+from typing_extensions import Literal
 
 from synapse.handlers.presence import UserPresenceState
 from synapse.module_api import ModuleApi