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