*/
<D extends DeclaredStatement<QName>, E extends EffectiveStatement<QName, D>>
@Nullable StmtContext<QName, D, E> requestSchemaTreeChild(QName qname);
*/
<D extends DeclaredStatement<QName>, E extends EffectiveStatement<QName, D>>
@Nullable StmtContext<QName, D, E> requestSchemaTreeChild(QName qname);