input: Write a python function to remove a specific word from a sentence.
  assert remove_word("the quick brown fox jumps over the lazy dog", "the") == "quick brown fox jumps over lazy dog"
  assert remove_word("the quick brown fox jumps over the lazy dog", "fox") == "the quick brown jumps over the lazy dog"
  assert remove_word("hello world", "world") == "hello"
output: def remove_word(sentence, word):
      words = sentence.split()
      words = [w for w in words if w != word]
      return " ".join(words)