input: Write a python function to reverse each word in a given sentence while maintaining their original positions.
  assert reverseSentence("Hello World") == "olleH dlroW"
  assert reverseSentence("Python is fun") == "nohtyP si nuf"
  assert reverseSentence("OpenAI is amazing") == "IAnepO si gnizama"
output: def reverseSentence(sentence):
      return ' '.join(word[::-1] for word in sentence.split())