input: Write a function that takes two string variables and prints them on the same line separated by a space. The function should accept two parameters, string1 and string2, and use the print function to display them concatenated with a space in between. If either string is empty, the function should still print the non-empty string followed by a space.
  
  def print_strings(string1, string2):
      print(string1 + " " + string2)
  
  assert print_strings("Hello", "World") == None
  assert print_strings("", "World") == None
  assert print_strings("Hello", "") == None
  assert print_strings("", "") == None
output: def print_strings(string1, string2):
      print(string1 + " " + string2)