input: Write a python function to convert a sentence into a list of words.
  assert convert_to_list("The quick brown fox jumped over the lazy dog.") == ['The', 'quick', 'brown', 'fox', 'jumped', 'over', 'the', 'lazy', 'dog.']
  assert convert_to_list("Hello world!") == ['Hello', 'world!']
  assert convert_to_list("") == []
output: def convert_to_list(sentence):
      return sentence.split()