4.3. Exercise: Maximum Occurrence

Write a function named maximum_occurrence which takes one input as a list of integers and returns the integer in the list that occurs the most. It is guaranteed that the number of occurrences of items in the list will be different from each other.

Sample I/O:

>>> maximum_occurrence([1,1,1,0,4,4])
1

>>> maximum_occurrence([0,3,3,3,1,0])
3