How to upgrade this code to dots 1.0.16 | Official Unity Discord | Page 1

my code is

    _buildPhysicsWorld = World.GetOrCreateSystem<BuildPhysicsWorld>();

it works on dots 0.50
but it failed on v1.0.16.
Cannot implicitly convert type 'Unity.Entities.SystemHandle' to 'Unity.Physics.Systems.BuildPhysicsWorld'
How to upgrade this code to dots 1.0.16?

#How to upgrade this code to dots 1.0.16