input: Write a function to get the frequencies of elements in a list.
  assert get_frequencies([1, 2, 2, 3, 3, 3])=={1: 1, 2: 2, 3: 3}
  assert get_frequencies(['a', 'b', 'a', 'a', 'c', 'b'])=={'a': 3, 'b': 2, 'c': 1}
  assert get_frequencies([True, False, True, True, False])=={True: 3, False: 2}
output: def get_frequencies(lst):
      frequencies = {}
      for item in lst:
          if item in frequencies:
              frequencies[item] += 1
          else:
              frequencies[item] = 1
      return frequencies