input: Write a python function to count the occurrences of a word in a sentence.
  assert countWordOccurrences("This is an example sentence", "example") == 1
  assert countWordOccurrences("This is an example sentence and this is another example", "example") == 2
  assert countWordOccurrences("example example example example", "example") == 4
output: def countWordOccurrences(sentence, word):
      return sentence.split().count(word)