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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 _text_image(page):
 """ returns text image URL """

    img = None
    alt = page.data.get('label') or page.data.get('title')
    source = _image(page)
    if source:
        img = "![%s](%s)" % (alt, source)
    return img