input: Write a python function to count the frequency of elements in a list.
  assert count_frequency([1, 8, 9, 11, 2, 10, 1, 5, 6, 8]) == {1: 2, 8: 2, 9: 1, 11: 1, 2: 1, 10: 1, 5: 1, 6: 1}
  assert count_frequency([4, 4, 4, 4, 4]) == {4: 5}
  assert count_frequency([3, 1, 2, 2, 3, 1, 3]) == {3: 3, 1: 2, 2: 2}
output: def count_frequency(lst):
      frequency = {}
      for item in lst:
          if item in frequency:
              frequency[item] += 1
          else:
              frequency[item] = 1
      return frequency