<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 async def on_raw_account(self, message):
 """ Changes in the associated account for a nickname. """

        if not self._capabilities.get('account-notify', False):
            return

        nick, metadata = self._parse_user(message.source)
        account = message.params[0]

        if nick not in self.users:
            return

        self._sync_user(nick, metadata)
        if account == NO_ACCOUNT:
            self._sync_user(nick, { 'account': None, 'identified': False })
        else:
            self._sync_user(nick, { 'account': account, 'identified': True })