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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_query_values_from_url(url, keys=None):
 """Gets query string values from a url. if a list of keys are provided, then a dict will be returned. If only a single string key is provided, then only a single value will be returned. "5" {'test': '5'} {'test': '5', 'john': 'doe'} {'test': '5', 'john': 'doe', 'blah': None} """

    if not url or '?' not in url:
        # no query params
        return None

    parsed_url = urlparse(url)
    query = dict(parse_qsl(parsed_url.query))

    if keys is None:
        return query

    if isinstance(keys, string_types):
        return query.get(keys)

    return {k: query.get(k) for k in keys}