def get_package_url(cls, package, session=None, silent=False):
        response = get("{}/packages/{}".format(cls.bower_base_uri, package))
        return response.json().get("url", None)
def forcedens(title, pos, fdens, ax=0):
    """plot force densities"""
    if ax == 0:
        ax = plt.gca()
    ax.set_title(title)
    ax.grid(True)

    ax.plot(pos, [1e-3*ft for ft in fdens[0]], label='F tang')
    ax.plot(pos, [1e-3*fn for fn in fdens[1]], label='F norm')
    ax.legend()
    ax.set_xlabel('Pos / deg')
    ax.set_ylabel('Force Density / kN/m²')