/// <private/>
        protected void _BuildConstraints(BuildArmaturePackage dataPackage, Armature armature)
        {
            var constraints = dataPackage.armature.constraints;

            foreach (var constraintData in constraints.Values)
            {
                // TODO more constraint type.
                var constraint = BaseObject.BorrowObject <IKConstraint>();
                constraint.Init(constraintData, armature);
                armature._AddConstraint(constraint);
            }
        }