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