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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 _add_data_attribute(self, data_attr):
 """Add a data attribute to the datastream structure. Data attributes require processing before they can be interpreted as datastream. This function grants that it is adding the attribute to the correct datastream or creating a new datastream if necessary. """

        attr_name = data_attr.header.attr_name

        stream = self._find_datastream(attr_name)
        if stream is None:
            stream = Datastream(attr_name)
            self.data_streams.append(stream)
        stream.add_data_attribute(data_attr)