def test_non_callable(self):
        with pytest.raises(TypeError) as excinfo:
            event.event(123)
        excinfo.match(r"Expected string, callable or None as first argument")

        with pytest.raises(TypeError) as excinfo:
            event.event("name")([])
        excinfo.match(r"Callable must be a function \(`def`\)"
                      r" or coroutine function \(`async def`\)")
def forcedens_surface(fdens, ax=0):
    if ax == 0:
        _create_3d_axis()
        ax = plt.gca()
    xpos = [p for p in fdens.positions[0]['X']]
    ypos = [p['position'] for p in fdens.positions]
    z = 1e-3*np.array([p['FN']
                       for p in fdens.positions])
    _plot_surface(ax, xpos, ypos, z,
                  (u'Rotor pos/°', u'Pos/°', u'F N / kN/m²'))