input: Write a function to convert a positive integer to negative or vice versa using the bitwise NOT operator. The function should be named `convert_numbers` and should take an integer as input. If the input is positive, the function should return the negative equivalent. If the input is negative, the function should return the positive equivalent. If the input is zero, the function should return zero.
  assert convert_numbers(5) == -5
  assert convert_numbers(-3) == 3
  assert convert_numbers(0) == 0
  assert convert_numbers(10) == -10
  assert convert_numbers(-7) == 7
output: def convert_numbers(num):
      if num == 0:
          return 0
      return -num