input: Write a python function to find the longest word in a sentence.
  assert find_longest_word("My name is John") == "name"
  assert find_longest_word("The quick brown fox jumps over the lazy dog") == "jumps"
  assert find_longest_word("Python programming is fun and educational") == "programming"
output: def find_longest_word(sentence):
      words = sentence.split()
      longest_word = max(words, key=len)
      return longest_word