input: Write a function to find the squares of numbers in a list.
  assert find_squares([1, 2, 3, 4, 5]) == [1, 4, 9, 16, 25]
  assert find_squares([6, 7, 8, 9, 10]) == [36, 49, 64, 81, 100]
  assert find_squares([-1, -2, -3, -4, -5]) == [1, 4, 9, 16, 25]
output: def find_squares(numbers):
      return [x**2 for x in numbers]