@staticmethod
def _classification_function_one(att1, att2, att3):
    """ classification_function_one

        Decides the sample class label based on the sum of att1 and att2, 
        and the threshold value of 9.

        Parameters
        ----------
        att1: float
            First numeric attribute.

        att2: float
            Second numeric attribute.

        att3: float
            Third numeric attribute.

        Returns
        -------
        int
            Returns the sample class label, either 0 or 1.

        """
    return 0 if att1 + att2 <= 9 else 1
