input: Write a python function to count the occurrences of a word in a given sentence.
  assert count_word_occurrences("the quick brown fox jumps over the lazy dog", "the") == 2
  assert count_word_occurrences("hello world hello", "hello") == 2
  assert count_word_occurrences("test the function test it well", "test") == 2
output: def count_word_occurrences(sentence, word):
      return sentence.split().count(word)