input: Write a function to store the strings "Hello" and "World" and print them in the same line. If the strings are empty, print "Strings are empty".
  assert store_and_print("Hello", "World")
  assert store_and_print("", "")=="Strings are empty"
  assert store_and_print("Hello", "")
  assert store_and_print("", "World")
output: def store_and_print(str1, str2):
      if str1 == "" and str2 == "":
          print("Strings are empty")
      else:
          print(str1 + " " + str2)