shutter: fix clear, error

ptb/shutter_protocol.py

@@ -37,11 +37,17 @@ async def status(self):
                 `True` means that there is an error.
         """
         ret = (await self.ask(b"e")).strip()
-        return tuple(bool(int(_)) for _ in ret)
+        return tuple(c != b"0"[0] for c in ret)
 
-    def clear(self):
-        """Clear all error flags."""
-        self.do(b"r")
+    async def clear(self):
+        """Clear all error flags.
+        
+        Returns:
+            tuple(bool): Error flag on all channels after clearing.
+                `True` means that there is an error.
+        """
+        ret = (await self.ask(b"r")).strip()
+        return tuple(c != b"0"[0] for c in ret)
 
     async def passthrough(self, shutter, cmd):
         """Execute a low level command.

test_shutter.py

@@ -9,12 +9,13 @@
 async def test(dev):
     print(dev)
     print(await dev.status())
+    print(await dev.clear())
     print(await dev.version())
     for i in b"WZ":  # STWXYZ
-        print(i, await dev.passthrough(1, i))
+        print(chr(i), await dev.passthrough(1, i))
 
 def main():
-    logging.basicConfig(level=logging.DEBUG)
+    #logging.basicConfig(level=logging.DEBUG)
     loop = asyncio.get_event_loop()
     loop.set_debug(False)
     async def run():