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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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