def _format_facetgrid(fg, units, yval='Concentration', xlabels=None):
    """
    Rotates the ticklabels, sets the yscale='log', etc
    """
    fg.set_xticklabels(
        labels=xlabels,
        rotation=30,
        rotation_mode='anchor',
        horizontalalignment='right'
    )
    fg.set(yscale='log')
    fg.set_xlabels('')
    fg.set_axis_labels(x_var='', y_var='{} ({})'.format(yval, units))
    return fg