@classmethod
def _split(cls, text, end='\n'):
    """Replace sentence boundaries with newlines and append a newline.

        :param text: string to line break at sentences
        :param end: appended to the end of the update text

        >>> Markdown._split("Hello, world!", end='')
        'Hello, world!'

        >>> Markdown._split("Hello, world! How are you? I'm fine. Good.")
        "Hello, world!\\nHow are you?\\nI'm fine.\\nGood.\\n"

        """
    stripped = text.strip()
    if stripped:
        return cls.REGEX_SENTENCE_BOUNDARIES.sub('\n', stripped) + end
    else:
        return ''
