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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 from_query_string(cls, schema, qs=None):
 """ Extract a page from the current query string. :param qs: a query string dictionary (`request.args` will be used if omitted) """

        dct = load_query_string_data(schema, qs)
        return cls.from_dict(dct)