input: Write a function to create a dictionary that maps each number in the given list to its square. The function should accept a list of integers as input and return a dictionary where the key is the number and the value is its square.
  
  def square_dict(numbers):
      return {num: num**2 for num in numbers}
  
  assert square_dict([1, 2, 3, 4, 5])=={1: 1, 2: 4, 3: 9, 4: 16, 5: 25}
  assert square_dict([0, -1, -2, 3, 4])=={0: 0, -1: 1, -2: 4, 3: 9, 4: 16}
  assert square_dict([])=={}
  assert square_dict([10])=={10: 100}
output: def square_dict(numbers):
      return {num: num**2 for num in numbers}