input: Write a function to create a dictionary that contains a data structure in the form of [x:x^2] where x is the key and x^2 is the value.
  
  assert create_dict_squares([1, 2, 3, 4, 5]) == {1: 1, 2: 4, 3: 9, 4: 16, 5: 25}
  assert create_dict_squares([]) == {}
  assert create_dict_squares([0]) == {0: 0}
  assert create_dict_squares([10, 20, 30]) == {10: 100, 20: 400, 30: 900}
  assert create_dict_squares([-1, -2, -3]) == {-1: 1, -2: 4, -3: 9}
output: def create_dict_squares(lst):
      return {x: x**2 for x in lst}