input: Write a function to concatenate two given strings "Hello" and "World" with a space in between and print the result. 
  
  assert concat_and_print("Hello", "World")==None
  
  The expected output should be "Hello World" printed to the console.
output: def concat_and_print(str1, str2):
      result = str1 + " " + str2
      print(result)