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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 select_features(self, *args, **kwargs):
 """ Select one or more fields as feature fields. :rtype: DataFrame """

        if not args:
            raise ValueError("Field list cannot be empty.")
        # generate selected set from args
        augment = kwargs.get('add', False)
        fields = _render_field_set(args)
        self._assert_ml_fields_valid(*fields)
        return _batch_change_roles(self, fields, FieldRole.FEATURE, augment)