def add_text_to_ax(x_coord, y_coord, string, ax, fontsize=12, color='k'):
    """ Shortcut to add text to an ax with proper font. Relative coords."""
    ax.text(x_coord, y_coord, string, family='monospace', fontsize=fontsize,
            transform=ax.transAxes, verticalalignment='top', color=color)
    return None