def _g_1(self):
        """omega1 < omega < omega2"""
        # return 3 * self._n_1() / (self._omega - self._vertices_omegas[0])
        return (3 * self._f(1, 0) * self._f(2, 0) /
                (self._vertices_omegas[3] - self._vertices_omegas[0]))
def _g_1 ( self ) : return ( 3 * self . _f ( 1 , 0 ) * self . _f ( 2 , 0 ) / ( self . _vertices_omegas [ 3 ] - self . _vertices_omegas [ 0 ] ) )
omega1 < omega < omega2