input: Write a function to delete every second word in a given string.
  assert delete_every_second_word("The quick brown fox jumps over the lazy dog") == "The brown jumps the dog"
  assert delete_every_second_word("One two three four five six") == "One three five"
  assert delete_every_second_word("Python is a great programming language") == "Python a programming"
output: def delete_every_second_word(s):
      words = s.split()
      return ' '.join(words[i] for i in range(len(words)) if i % 2 == 0)