input: Write a python function to find the sum of even numbers in a list.
  assert sum_of_even_numbers([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == 30
  assert sum_of_even_numbers([10, 20, 45, 67, 84, 93]) == 114
  assert sum_of_even_numbers([5, 7, 9, 8, 6, 4, 3]) == 18
output: def sum_of_even_numbers(lst):
      return sum(x for x in lst if x % 2 == 0)