Vertex color to material blender

VertexColorToMaterial.py

import bpy

def create_material(color_name, color):
    # Create a new material with the given color
    mat = bpy.data.materials.new(name=color_name)
    mat.use_nodes = True
    nodes = mat.node_tree.nodes
    principled_bsdf = nodes.get("Principled BSDF")
    
    if principled_bsdf is not None:
        principled_bsdf.inputs["Base Color"].default_value = (color)
    else:
        diffuse_shader = nodes.get("Diffuse BSDF")
        if diffuse_shader is not None:
            diffuse_shader.inputs["Color"].default_value = (color)
    return mat

# Get active object
obj = bpy.context.active_object
if obj is not None and obj.type == "MESH" and obj.data.vertex_colors:

    vertex_colors = obj.data.vertex_colors.active.data
    # Dictionary to store unique colors
    unique_colors = {}
    # Loop through each vertex
    for loop_idx, loop in enumerate(obj.data.loops):
        color = vertex_colors[loop_idx].color
        # Round color vgalues
        rounded_color = tuple(round(c, 3) for c in color)
        # Add the color to the dictionary if it doesn't exist already
        if rounded_color not in unique_colors:
            unique_colors[rounded_color] = []
        # Append the vertex index to the list associated with the color
        unique_colors[rounded_color].append(loop.vertex_index)
    
    # Create a material for each unique color
    for idx, (color, vertex_indices) in enumerate(unique_colors.items()):
        color_name = f"ColorMaterial_{idx}"
        material = create_material(color_name, color)

        # Assign the material to the selected vertices
        bpy.context.view_layer.objects.active = obj
        bpy.ops.object.mode_set(mode='EDIT')
        bpy.ops.mesh.select_all(action='DESELECT')
        bpy.ops.object.mode_set(mode='OBJECT')

        for vertex_index in vertex_indices:
            obj.data.vertices[vertex_index].select = True
        bpy.context.view_layer.objects.active = obj
        bpy.ops.object.material_slot_add()
        obj.data.materials[-1] = material

        bpy.ops.object.mode_set(mode='OBJECT')

        # Link the material to the corresponding faces
        for poly in obj.data.polygons:
            for loop_index in poly.loop_indices:
                vertex_index = obj.data.loops[loop_index].vertex_index
                if vertex_index in vertex_indices:
                    poly.material_index = len(obj.data.materials) - 1
                    break

    bpy.ops.object.mode_set(mode='OBJECT')
    bpy.context.view_layer.update()