input: Write a python function to check if a list contains duplicates.
  assert check_duplicates([3, 5, 8, 1, 2, 3])==True
  assert check_duplicates([1, 2, 3, 4, 5])==False
  assert check_duplicates([7, 7, 7, 7, 7])==True
  assert check_duplicates([])==False
output: def check_duplicates(lst):
      return len(lst) != len(set(lst))