input: Write a python function to calculate the dot product of two lists.
  assert dot_product([1, 2, 3], [4, 5, 6]) == 32
  assert dot_product([0, 1, 0], [0, 0, 1]) == 0
  assert dot_product([1, 2], [1, 2]) == 5
output: def dot_product(list1, list2):
      return sum(a * b for a, b in zip(list1, list2))