How store array of Vector in properties?

I tried something simple:

bpy.types.Group.BBoxVertsList = [Vector((0,0,0))]*20

But it won’t be saved in blend file. I can create something like this

class Location(bpy.types.PropertyGroup):
    loc = bpy.props.FloatVectorProperty(subtype = 'TRANSLATION')


bpy.utils.register_class(Location)




bpy.types.Group.BBoxVertsList = bpy.props.PointerProperty(type = Location)

But it dosen’t seem efficient to create loc property one by one by add() method.

I know obj.bounding_box has solved it somehow, it is float list, but user can call each element of bounding box[x], and get location of vertices. But I’m don’t know how it is done - getting vert location, from what it seems flat list of floats…

Custom properties can only be stored using bpy.props and ID properties, you can’t use built-in python types. bound_box is an internal property, not python-defined.