<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def feed_interval_delete(feed_id, parameters):
	'Invalidate cached adaptive interval value.'
	cache.delete(getkey( T_INTERVAL,
		key=feed_interval_key(feed_id, parameters) ))