5e948879a7cad7ead540fc7132db0d2d6bb379bb,bokeh/plotting/_graph.py,,get_graph_kwargs,#Any#Any#,52

Before Change

        else:
            marker_type = marker_types.get(marker)
    if marker_type is None:
        msg = "Could not determine marker type for node_marker={marker}".format(marker=repr(marker))
        raise ValueError(msg)

    //// node stuff
    node_visuals = pop_visuals(marker_type, kwargs, prefix="node_")

After Change

        if marker is None or marker == "circle":
            marker_type = Circle
        else:
            kwargs["node_marker"] = marker

    //// node stuff
    node_visuals = pop_visuals(marker_type, kwargs, prefix="node_")

Instances