input: Write a python function to check if a list contains any even numbers.
  assert check_even([1, 3, 5, 7]) == False
  assert check_even([1, 2, 3, 5]) == True
  assert check_even([2, 4, 6, 8]) == True
output: def check_even(lst):
      for num in lst:
          if num % 2 == 0:
              return True
      return False