def groups_option(f):
    new_func = click.option("-g", "--groups",
                            help="Comma-separated list of requirement groups "
                            "to include.")(f)
    return update_wrapper(new_func, f)
def winding_current(pos, current, ax=0):
    """plot winding currents"""
    if ax == 0:
        ax = plt.gca()
    ax.set_title('Winding Currents / A')
    ax.grid(True)
    for p, i in zip(pos, current):
        ax.plot(p, i)