input: Write a function to add two numbers together and print the result. The function should take two parameters, a and b, and return the sum by printing it out.
  
  def add(a, b):
      sum = a + b
      print(sum)
  
  add(5,7)
  add(10,20)
  add(-3,3)
  add(0,0)
  add(99,1)
output: def add(a, b):
      sum = a + b
      print(sum)