Question: 
Write a function to find frequency of the elements in a given list of lists using collections module.


Model's Code:
from collections import Counter

def freq_element(lst):
    flat_list = [item for sublist in lst for item in sublist]
    return dict(Counter(flat_list))



Sample Correct Code:
from collections import Counter
from itertools import chain
def freq_element(nums):
  result = Counter(chain.from_iterable(nums))
  return result


Asserts:
assert freq_element([[1, 2, 3, 2], [4, 5, 6, 2], [7, 1, 9, 5]])==({2: 3, 1: 2, 5: 2, 3: 1, 4: 1, 6: 1, 7: 1, 9: 1})
assert freq_element([[1,2,3,4],[5,6,7,8],[9,10,11,12]])==({1: 1, 2: 1, 3: 1, 4: 1, 5: 1, 6: 1, 7: 1, 8: 1, 9: 1, 10: 1, 11: 1, 12: 1})
assert freq_element([[15,20,30,40],[80,90,100,110],[30,30,80,90]])==({30: 3, 80: 2, 90: 2, 15: 1, 20: 1, 40: 1, 100: 1, 110: 1})


Tests:
Test 1 of 3: PASS
Test 2 of 3: PASS
Test 3 of 3: PASS

Test 40 of 974: 31/40 (77.5%): success