def main(ctx):
    which = "where" if sys.platform == "win32" else "which"
    if envoy.run(which + " git").status_code != 0:
        click.secho("fatal: git not found in PATH", fg="red")
        sys.exit(1)
    ctx.obj = Hydrogen()
def i1beta_up(i1, beta, up, ax=0):
    """creates a surface plot of up vs i1, beta"""
    if ax == 0:
        _create_3d_axis()
        ax = plt.gca()
    _plot_surface(ax, i1, beta, up,
                  (u'I1/A', u'Beta/°', u'Up/V'),
                  azim=60)