Don't explode when function doesn't get implemented

Closes https://git.autonomic.zone/decentral1se/xbotlib/issues/18.

CHANGELOG.md

@@ -1,5 +1,9 @@
 # xbotlib x.x.x (UNRELEASED)
 
+# xbotlib 0.8.0 (2021-01-14)
+
+- Support not providing response implementation ([#18](https://git.autonomic.zone/decentral1se/xbotlib/issues/18))
+
 # xbotlib 0.7.1 (2021-01-13)
 
 - Support logging ([#2](https://git.autonomic.zone/decentral1se/xbotlib/issues/2))

xbotlib.py

@@ -138,7 +138,10 @@ class Bot(ClientXMPP):
     def direct_message(self, message):
         """Handle message event."""
         if message["type"] in ("chat", "normal"):
+            try:
                 self.direct(SimpleMessage(message))
+            except AttributeError:
+                self.log.info("Bot.direct not implemented")
 
     def session_start(self, message):
         """Handle session_start event."""
@@ -155,7 +158,10 @@ class Bot(ClientXMPP):
         """Handle groupchat_message event."""
         if message["type"] in ("groupchat", "normal"):
             if message["mucnick"] != self.config["bot"]["nick"]:
+                try:
                     self.group(SimpleMessage(message))
+                except AttributeError:
+                    self.log.info("Bot.group not implemented")
 
     def register_xmpp_plugins(self):
         """Register XMPP plugins that the bot supports."""