Fix hint errors in microgrid client

The tool mypy is not able to infer the types of the gRPC calls,
so we need to cast them to the correct type in order to avoid
the errors.

Signed-off-by: Daniel Zullo <[email protected]>

Author: daniel-zullo-frequenz

src/frequenz/sdk/microgrid/client/_client.py

@@ -239,10 +239,14 @@ async def components(self) -> Iterable[Component]:
         try:
             # grpc.aio is missing types and mypy thinks this is not awaitable,
             # but it is
-            component_list = await self.api.ListComponents(
-                microgrid_pb.ComponentFilter(),
-                timeout=int(DEFAULT_GRPC_CALL_TIMEOUT),
-            )  # type: ignore[misc]
+            component_list = await cast(
+                Awaitable[microgrid_pb.ComponentList],
+                self.api.ListComponents(
+                    microgrid_pb.ComponentFilter(),
+                    timeout=int(DEFAULT_GRPC_CALL_TIMEOUT),
+                ),
+            )
+
         except grpc.aio.AioRpcError as err:
             msg = f"Failed to list components. Microgrid API: {self.target}. Err: {err.details()}"
             raise grpc.aio.AioRpcError(
@@ -280,10 +284,13 @@ async def metadata(self) -> Metadata:
         """
         microgrid_metadata: microgrid_pb.MicrogridMetadata | None = None
         try:
-            microgrid_metadata = await self.api.GetMicrogridMetadata(
-                Empty(),
-                timeout=int(DEFAULT_GRPC_CALL_TIMEOUT),
-            )  # type: ignore[misc]
+            microgrid_metadata = await cast(
+                Awaitable[microgrid_pb.MicrogridMetadata],
+                self.api.GetMicrogridMetadata(
+                    Empty(),
+                    timeout=int(DEFAULT_GRPC_CALL_TIMEOUT),
+                ),
+            )
         except grpc.aio.AioRpcError:
             _logger.exception("The microgrid metadata is not available.")
 
@@ -616,12 +623,15 @@ async def set_power(self, component_id: int, power_w: float) -> None:
                 when the api call exceeded timeout
         """
         try:
-            await self.api.SetPowerActive(
-                microgrid_pb.SetPowerActiveParam(
-                    component_id=component_id, power=power_w
+            await cast(
+                Awaitable[microgrid_pb.SetPowerActiveParam],
+                self.api.SetPowerActive(
+                    microgrid_pb.SetPowerActiveParam(
+                        component_id=component_id, power=power_w
+                    ),
+                    timeout=int(DEFAULT_GRPC_CALL_TIMEOUT),
                 ),
-                timeout=int(DEFAULT_GRPC_CALL_TIMEOUT),
-            )  # type: ignore[misc]
+            )
         except grpc.aio.AioRpcError as err:
             msg = f"Failed to set power. Microgrid API: {self.target}. Err: {err.details()}"
             raise grpc.aio.AioRpcError(