Add a comment about the - version split

octodns/provider/powerdns.py

@@ -183,6 +183,8 @@ class PowerDnsBaseProvider(BaseProvider):
             version = resp.json()['version']
             self.log.debug('powerdns_version: got version %s from server',
                            version)
+            # The extra `-` split is to handle pre-release and source built 
+            # versions like 4.5.0-alpha0.435.master.gcb114252b
             self._powerdns_version = [
                 int(p.split('-')[0]) for p in version.split('.')[:3]]