Added the HandlerFailure exception

kayleevc/kaylee.py

                 break
             except queue.Empty:
                 break
-                # If an unknown error occurs, ignore it and keep trying
-                # FIXME not a good API decision
+            except kayleevc.plugins.HandlerFailure:
+                # If the handler failed, keep trying
+                continue
 
         self._stop_ui(text)
 

kayleevc/plugins/__init__.py

 
         When called, ``tts`` is a function which takes a string as its only
         parameter and passes it to Kaylee's configured text-to-speech system.
+
+        If command handling fails for some reason that can be anticipated, this
+        method must raise a HandlerFailure to tell Kaylee to keep trying other
+        handlers.
         """
 
     def __eq__(self, other):
             # Intentionally reversed
             return (self.confidence < other.confidence)
         return NotImplemented
+
+
+class HandlerFailure(Exception):
+    """Handler failed to handle its command."""

kayleevc/plugins/mpris.py

 from gi.repository import GLib
 from pydbus import SessionBus
 
-from . import PluginBase, Handler
+from . import PluginBase, Handler, HandlerFailure
 
 
 class Plugin(PluginBase):
         try:
             self.proxy.Next()
         except GLib.Error:
-            # This error is raised if the media player was closed after we got
-            # the proxy but before we called next.
-            # FIXME raise a different exception to tell Kaylee that we failed
-            pass
+            raise HandlerFailure()
 
 
 class MPRISPauseHandler(MPRISHandler):
         try:
             self.proxy.Pause()
         except GLib.Error:
-            # This error is raised if the media player was closed after we got
-            # the proxy but before we called pause.
-            # FIXME raise a different exception to tell Kaylee that we failed
-            pass
+            raise HandlerFailure()
 
 
 class MPRISPlayHandler(MPRISHandler):
         try:
             self.proxy.Play()
         except GLib.Error:
-            # This error is raised if the media player was closed after we got
-            # the proxy but before we called play.
-            # FIXME raise a different exception to tell Kaylee that we failed
-            pass
+            raise HandlerFailure()
 
 
 class MPRISPreviousHandler(MPRISHandler):
         try:
             self.proxy.Previous()
         except GLib.Error:
-            # This error is raised if the media player was closed after we got
-            # the proxy but before we called previous.
-            # FIXME raise a different exception to tell Kaylee that we failed
-            pass
+            raise HandlerFailure()