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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 fromstring(cls, string):
 """ Create a METS by parsing a string. :param str string: String containing a METS document. """

        parser = etree.XMLParser(remove_blank_text=True)
        root = etree.fromstring(string, parser)
        tree = root.getroottree()

        return cls.fromtree(tree)