'Return the muted user involved in a modmail conversation (if any).'

def get_muted_user_in_conversation(self):

    if (not self.sr_id):
        return None
    sr = self.subreddit_slow
    if self.first_message:
        first = Message._byID(self.first_message, data=True)
    else:
        first = self
    first_author = first.author_slow
    first_recipient = (first.recipient_slow if first.to_id else None)
    if sr.is_muted(first_author):
        return first_author
    elif (first_recipient and sr.is_muted(first_recipient)):
        return first_recipient
    else:
        return None
