input: Write a function that takes two strings as input, concatenates them with a space in between, and prints the result.
  
  def concat_and_print(string1, string2):
      print(string1 + " " + string2)
  
  assert concat_and_print("Hello", "World")==None
output: def concat_and_print(string1, string2):
      print(string1 + " " + string2)