input: Write a function to create a dictionary with the elements of the list as keys and the product of each element as values. The product of each element is calculated as the element multiplied by itself.
  assert product_of_list([7, 8, 5])=={7: 49, 8: 64, 5: 25}
  assert product_of_list([4, 2, 9])=={4: 16, 2: 4, 9: 81}
  assert product_of_list([1, 3, 6])=={1: 1, 3: 9, 6: 36}
  assert product_of_list([0, 5, 10])=={0: 0, 5: 25, 10: 100}
  assert product_of_list([])=={}
output: def product_of_list(lst):
      return {x: x * x for x in lst}