<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def preLoad(self):
 """ Store audio data in cache for fast playback. """

    logging.getLogger().debug("Preloading segment '%s'" % (self))
    real_url = self.buildUrl()
    cache_url = self.buildUrl(cache_friendly=True)
    audio_data = self.download(real_url)
    assert(audio_data)
    __class__.cache[cache_url] = audio_data