Add more py37 typing hacks

sanic/models/protocol_types.py

@@ -0,0 +1,44 @@
+import sys
+
+from typing import Any, AnyStr, TypeVar, Union
+
+
+if sys.version_info < (3, 8):
+    from asyncio import BaseTransport
+
+    # from sanic.models.asgi import MockTransport
+    MockTransport = TypeVar("MockTransport")
+
+    TransportProtocol = Union[MockTransport, BaseTransport]
+    Range = Any
+    HTMLProtocol = Any
+else:
+    # Protocol is a 3.8+ feature
+    from typing import Protocol
+
+    class TransportProtocol(Protocol):
+        def get_protocol(self):
+            ...
+
+        def get_extra_info(self, info: str) -> Union[str, bool, None]:
+            ...
+
+    class HTMLProtocol(Protocol):
+        def __html__(self) -> AnyStr:
+            ...
+
+        def _repr_html_(self) -> AnyStr:
+            ...
+
+    class Range(Protocol):
+        def start(self) -> int:
+            ...
+
+        def end(self) -> int:
+            ...
+
+        def size(self) -> int:
+            ...
+
+        def total(self) -> int:
+            ...