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, given a list of numbers.
  
  
  def create_dict(numbers):
      return {num: num**2 for num in numbers}
  
  # Testing cases
  assert create_dict([1, 2, 3, 4, 5]) == {1: 1, 2: 4, 3: 9, 4: 16, 5: 25}
  assert create_dict([0, -1, -2, -3]) == {0: 0, -1: 1, -2: 4, -3: 9}
  assert create_dict([]) == {}
  assert create_dict([-5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5]) == {-5: 25, -4: 16, -3: 9, -2: 4, -1: 1, 0: 0, 1: 1, 2: 4, 3: 9, 4: 16, 5: 25}
  
output: def create_dict(numbers):
      return {num: num**2 for num in numbers}