Pattern: PFunc
Returns the value generated by a function.
Useful to incorporate additional logic into a pattern.
Example output
>>> seconds = PFunc(lambda: datetime.datetime.now().second)
>>> p.nextn(16)
[19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19]