input: Write a function that takes a list as input and prints a dictionary with the elements and the product of each element.
  assert product_of_list([7, 8, 5]) == {7: 49, 8: 64, 5: 25}
  assert product_of_list([3, 4, 5, 6]) == {3: 9, 4: 16, 5: 25, 6: 36}
  assert product_of_list([]) == {}
  assert product_of_list([1, 1, 1, 1]) == {1: 1}
  assert product_of_list([2]) == {2: 4}
output: def product_of_list(lst):
      return {x: x * x for x in lst}