正規表現の補完と説明

import re

def splitSentences(sentences):
  """
  Splits a string of sentences into a list.
  Each sentence is period-separated, save for cases where
  the phrases "Mr." or "Ms." are used, since those
  don't end a sentence.
  """
  sentenceList = []

  # missing code here

  return sentenceList

import re

def splitSentences(sentences):
  """
  Splits a string of sentences into a list.
  Each sentence is period-separated, save for cases where
  the phrases "Mr." or "Ms." are used, since those
  don't end a sentence.
  """
  sentenceList = []
  sentenceEnders = r'(?<!Mr)\.(?<![A-Z][a-z]\.)(?<![A-Z][a-z][a-z]\.)(?<=\.|\?)\s'
  sentenceList = re.split(sentenceEnders, sentences)
  return sentenceList