@NotNull
  @Override
  public GrExtendsClause createExtendsClause() {
    final GrTypeDefinition typeDefinition = createTypeDefinition("class A extends B {}");
    final GrExtendsClause clause = typeDefinition.getExtendsClause();
    clause.getReferenceElementsGroovy()[0].delete();
    return clause;
  }
@NotNull
  @Override
  public GrExtendsClause createExtendsClause()