def METHOD_NAME(self):
    min_coefs = numpy.min(self.inversion_coefs, axis=1) 
    max_coefs = numpy.max(self.inversion_coefs, axis=1) 
    min_slip = self._calc_slip(min_coefs)
    max_slip = self._calc_slip(max_coefs)
    return (min_slip, max_slip)