def METHOD_NAME(label, legend, glyph_renderer):
    if not isinstance(label, str):
        raise ValueError("legend_field value must be a string")
    label = field(label)
    item = _find_legend_item(label, legend)
    if item:
        item.renderers.append(glyph_renderer)
    else:
        new_item = LegendItem(label=label, renderers=[glyph_renderer])
        legend.items.append(new_item)