backends: winrt: allow multiple disconnect() calls

align WinRT implementation with other backends

Author: patman15

CHANGELOG.rst

@@ -18,6 +18,7 @@ Added
 Changed
 -------
 * Raise new ``BleakBluetoothNotAvailableError`` when Bluetooth is not supported, turned off or permission is denied.
+* Allow multiple calls to ``disconnect()`` on Windows to align behaviour over all backends.
 
 Fixed
 -----

bleak/backends/winrt/client.py

@@ -465,7 +465,12 @@ async def disconnect(self) -> None:
         """Disconnect from the specified GATT server."""
         logger.debug("Disconnecting from BLE device...")
 
-        assert self.services
+        if self.services is None:
+            # No connection exists. Either one hasn't been created or
+            # we have already called disconnect and closed the gatt
+            # connection.
+            logger.debug("already disconnected")
+            return
 
         # Remove notifications.
         for handle, event_handler_token in list(self._notification_callbacks.items()):