def _get_element_text_or_none(document, selector):
    """
    Using a CSS selector, get the element and return the text, or None if no element.

    :arg document: ``HTMLElement`` document
    :arg selector: CSS selector
    :returns: str or None
    """
    element = document.cssselect(selector)
    if element:
        return element[0].text
    return None