input: Write a function to convert a positive integer to negative or vice versa using bitwise NOT operator. If the input is a positive integer, the function should return its negative equivalent and if the input is a negative integer, it should return its positive equivalent.
  assert convert_to_negative(5)==-5
  assert convert_to_negative(-4)==4
  assert convert_to_positive(7)==-7
  assert convert_to_positive(-3)==3
  assert convert_to_negative(0)==0
output: def convert_to_negative(n):
      return ~n + 1
  
  def convert_to_positive(n):
      return ~n + 1