input: Write a function to convert a positive integer to negative or vice versa using bitwise NOT operator. The function should return the converted value.
  
  def convert_to_negative(x): 
      return ~x + 1 
    
  def convert_to_positive(x): 
      return ~(x-1)
  
  assert convert_to_negative(5) == -5
  assert convert_to_positive(-5) == 5
  assert convert_to_negative(-5) == 5
  assert convert_to_positive(5) == -5
output: def convert_to_negative(x): 
      return ~x + 1 
    
  def convert_to_positive(x): 
      return ~(x-1)