<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def selectlanguage(self, event):
 """Store client's selection of a new translation"""


        self.log('Language selection event:', event.client, pretty=True)

        if event.data not in all_languages():
            self.log('Unavailable language selected:', event.data, lvl=warn)
            language = None
        else:
            language = event.data

        if language is None:
            language = 'en'

        event.client.language = language

        if event.client.config is not None:
            event.client.config.language = language
            event.client.config.save()