input: Write a python function to tokenize a sentence into words and punctuations.
  assert tokenize("This is a sample sentence.") == (['This', 'is', 'a', 'sample', 'sentence'], ['.'])
  assert tokenize("Hello, world!") == (['Hello', 'world'], [',', '!'])
  assert tokenize("Python's syntax is easy-to-learn.") == (['Python', 's', 'syntax', 'is', 'easy', 'to', 'learn'], ["'","-","."])
output: def tokenize(sentence):
      import re
      words = re.findall(r'\b\w+\b', sentence)
      punctuations = re.findall(r'[^\w\s]', sentence)
      return words, punctuations