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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 unpack(self, buff, offset=0):
 """Discard padding bytes using the unpacked length attribute."""

        begin = offset
        for name, value in list(self.get_class_attributes())[:-1]:
            size = self._unpack_attribute(name, value, buff, begin)
            begin += size
        self._unpack_attribute('oxm_match_fields', type(self).oxm_match_fields,
                               buff[:offset+self.length], begin)