Contour plot of 2d DataArray

    Wraps :func:`matplotlib:matplotlib.pyplot.contour`

def contour(x, y, z, ax, **kwargs):
    """
    Contour plot of 2d DataArray

    Wraps :func:`matplotlib:matplotlib.pyplot.contour`
    """
    primitive = ax.contour(x, y, z, **kwargs)
    return primitive