// In TypeScript, protected means "any subclass can access parent fields on instances of itself"
// To work around this, we add accessors for other instances' protected fields here.
protected static add_ref_from(holder: CommonBase, referent: object) {
// In TypeScript, protected means "any subclass can access parent fields on instances of itself"
// To work around this, we add accessors for other instances' protected fields here.
protected static add_ref_from(holder: CommonBase, referent: object) {