add types

Author: graingert

src/outcome/_impl.py

@@ -190,7 +190,7 @@ async def asend(self, agen: AsyncGenerator[ResultT, ValueT]) -> ResultT:
         return await agen.asend(self.unwrap())
 
     @property
-    def value(self):
+    def value(self) -> ValueT:
         return self.unwrap()
 
 
@@ -250,7 +250,7 @@ async def asend(self, agen: AsyncGenerator[ResultT, NoReturn]) -> ResultT:
         return await agen.athrow(self._unwrap_error())
 
     @property
-    def error(self):
+    def error(self) -> BaseException:
         return self._unwrap_error()