input: Write a function to add two numbers together and print the result.
  def add(a, b):
      return a + b
  
  print(add(5, 7))
  print(add(3, 4))
  print(add(10, -2))
  print(add(0, 0))
  print(add(-5, 5))
output: def add(a, b):
      return a + b