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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 is_relative_url(url):
 """ simple method to determine if a url is relative or absolute """

    if url.startswith("#"):
        return None
    if url.find("://") > 0 or url.startswith("//"):
        # either 'http(s)://...' or '//cdn...' and therefore absolute
        return False
    return True