input: Write a function to create a dictionary that maps each number in a given list to its square. The keys in the dictionary should be the numbers from the list, and the values should be the squares of those numbers. If the input list is empty, the function should return an empty dictionary.
  
  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([]) == {}
  assert create_square_dict([0, -1, -2]) == {0: 0, -1: 1, -2: 4}
output: def create_square_dict(numbers):
      return {num: num**2 for num in numbers}