def METHOD_NAME(self, bus):
    r"""
    Calculate partial derivatives of the bus function.
    Parameters
    ----------
    bus : tespy.connections.bus.Bus
        TESPy bus object.
    Returns
    -------
    deriv : ndarray
        Matrix of partial derivatives.
    """
    deriv = np.zeros((1, 2, self.num_nw_vars))
    f = self.calc_bus_value
    deriv[0, 0, 0] = self.numeric_deriv(f, 'm', 0, bus=bus)
    deriv[0, 0, 2] = self.numeric_deriv(f, 'h', 0, bus=bus)
    deriv[0, 1, 2] = self.numeric_deriv(f, 'h', 1, bus=bus)
    return deriv