Update octodns/provider/mythicbeasts.py

Seems fair to me! I think a lot of the suggestions you've mentioned are obvious ones that have been lost on me from being very confused trying to understand the available objects

Co-Authored-By: Ross McFarland <ross@github.com>

octodns/provider/mythicbeasts.py

@@ -339,7 +339,7 @@ class MythicBeastsProvider(BaseProvider):
 
         base = '{} {} {} {}'.format(action, hostname, ttl, _type)
 
-        if re.match('[A]{1,4}', _type) is not None:
+        if _type in ('A', 'AAAA'):
             for value in values:
                 commands.append('{} {}'.format(base, value))