How to use the pythreejs.BufferAttribute function in pythreejs

edge_list = list(
                    map(
                        lambda i_edge:
                        [tess.GetEdgeVertex(i_edge, i_vert) for i_vert in range(tess.ObjEdgeGetVertexCount(i_edge))],
                        range(tess.ObjGetEdgeCount())))

            # END copy

        if vertices is not None:
            vertices_list = []
            for vertex in vertices:
                p = BRep_Tool.Pnt(vertex)
                vertices_list.append((p.X(), p.Y(), p.Z()))
            vertices_list = np.array(vertices_list, dtype=np.float32)

            attributes = {"position": BufferAttribute(vertices_list, normalized=False)}

            mat = PointsMaterial(color=vertex_color, sizeAttenuation=False, size=vertex_width)
            geom = BufferGeometry(attributes=attributes)
            points = Points(geometry=geom, material=mat)

        if edges is not None:
            start_discretize_time = self._start_timer()
            edge_list = [discretize_edge(edge, self.edge_accuracy) for edge in edges]
            self._stop_timer("discretize time",start_discretize_time)

        if edge_list is not None:
            edge_list = _flatten(list(map(_explode, edge_list)))
            lines = LineSegmentsGeometry(positions=edge_list)
            mat = LineMaterial(linewidth=edge_width, color=edge_color)
            edge_lines = LineSegments2(lines, mat, name="edges_%d" % shape_index)

def _render_obj(self, rendered_obj, **kw):        
        obj_geometry = pjs.BufferGeometry(attributes=dict(position=pjs.BufferAttribute(rendered_obj.plot_verts), 
                                                         color=pjs.BufferAttribute(rendered_obj.base_cols),
                                                         normal=pjs.BufferAttribute(rendered_obj.face_normals.astype('float32'))))
        vertices = rendered_obj.vertices
        
        # Create a mesh. Note that the material need to be told to use the vertex colors.        
        my_object_mesh = pjs.Mesh(
            geometry=obj_geometry,
            material=pjs.MeshLambertMaterial(vertexColors='VertexColors'),
            position=[0, 0, 0],   
        )
        
        line_material = pjs.LineBasicMaterial(color='#ffffff', transparent=True, opacity=0.3, linewidth=1.0)
        my_object_wireframe_mesh = pjs.LineSegments(
            geometry=obj_geometry,
            material=line_material,
            position=[0, 0, 0], 
        )

def AddCurveToScene(self, shp, color):
        """ shp is either a TopoDS_Wire or a TopodS_Edge.
        """
        if is_edge(shp):
            pnts = discretize_edge(shp)
        elif is_wire(shp):
            pnts = discretize_wire(shp)
        np_edge_vertices = np.array(pnts, dtype=np.float32)
        np_edge_indices = np.arange(np_edge_vertices.shape[0], dtype=np.uint32)
        edge_geometry = BufferGeometry(attributes={
            'position': BufferAttribute(np_edge_vertices),
            'index'   : BufferAttribute(np_edge_indices)
        })
        edge_material = LineBasicMaterial(color=color, linewidth=2, fog=True)
        edge_lines = LineSegments(geometry=edge_geometry, material=edge_material)

        # Add geometries to pickable or non pickable objects
        self._displayed_pickable_objects.add(edge_lines)

# then we build the vertex and faces collections as numpy ndarrays
            np_vertices = np.array(vertices_position, dtype='float32')\
                            .reshape(int(number_of_vertices / 3), 3)
            # Note: np_faces is just [0, 1, 2, 3, 4, 5, ...], thus arange is used
            np_faces = np.arange(np_vertices.shape[0], dtype='uint32')

            # compute normals
            np_normals = np.array(tess.GetNormalsAsTuple(), dtype='float32').reshape(-1, 3)
            if np_normals.shape != np_vertices.shape:
                raise AssertionError("Wrong number of normals/shapes")

            # build a BufferGeometry instance
            shape_geometry = BufferGeometry(
                attributes={
                    'position': BufferAttribute(np_vertices),
                    'index': BufferAttribute(np_faces),
                    'normal': BufferAttribute(np_normals)
                })

            shp_material = self._material(mesh_color, transparent=True, opacity=opacity)

            shape_mesh = Mesh(geometry=shape_geometry, material=shp_material, name="mesh_%d" % shape_index)

            if render_edges:
                edge_list = list(
                    map(
                        lambda i_edge:
                        [tess.GetEdgeVertex(i_edge, i_vert) for i_vert in range(tess.ObjEdgeGetVertexCount(i_edge))],
                        range(tess.ObjGetEdgeCount())))

            # END copy

if v.shape[1] == 2:
            v = np.append(v, np.zeros([v.shape[0], 1]), 1)


        # Type adjustment vertices
        v = v.astype("float32", copy=False)

        # Color setup
        colors, coloring = self.__get_colors(v, f, c, sh)

        # Type adjustment faces and colors
        c = colors.astype("float32", copy=False)

        # Material and geometry setup
        ba_dict = {"color": p3s.BufferAttribute(c)}
        if coloring == "FaceColors":
            verts = np.zeros((f.shape[0]*3, 3), dtype="float32")
            for ii in range(f.shape[0]):
                #print(ii*3, f[ii])
                verts[ii*3] = v[f[ii,0]]
                verts[ii*3+1] = v[f[ii,1]]
                verts[ii*3+2] = v[f[ii,2]]
            v = verts
        else:
            f = f.astype("uint32", copy=False).ravel()
            ba_dict["index"] = p3s.BufferAttribute(f, normalized=False)

        ba_dict["position"] = p3s.BufferAttribute(v, normalized=False)

        if type(uv) != type(None):
            uv = (uv - np.min(uv)) / (np.max(uv) - np.min(uv))

np_vertices = np.array(vertices_position, dtype='float32')\
                            .reshape(int(number_of_vertices / 3), 3)
            # Note: np_faces is just [0, 1, 2, 3, 4, 5, ...], thus arange is used
            np_faces = np.arange(np_vertices.shape[0], dtype='uint32')

            # compute normals
            np_normals = np.array(tess.GetNormalsAsTuple(), dtype='float32').reshape(-1, 3)
            if np_normals.shape != np_vertices.shape:
                raise AssertionError("Wrong number of normals/shapes")

            # build a BufferGeometry instance
            shape_geometry = BufferGeometry(
                attributes={
                    'position': BufferAttribute(np_vertices),
                    'index': BufferAttribute(np_faces),
                    'normal': BufferAttribute(np_normals)
                })

            shp_material = self._material(mesh_color, transparent=True, opacity=opacity)

            shape_mesh = Mesh(geometry=shape_geometry, material=shp_material, name="mesh_%d" % shape_index)

            if render_edges:
                edge_list = list(
                    map(
                        lambda i_edge:
                        [tess.GetEdgeVertex(i_edge, i_vert) for i_vert in range(tess.ObjEdgeGetVertexCount(i_edge))],
                        range(tess.ObjGetEdgeCount())))

            # END copy

        if vertices is not None: