@NotNull
  @Override
  public GrImplementsClause createImplementsClause() {
    final GrTypeDefinition typeDefinition = createTypeDefinition("class A implements B {}");
    final GrImplementsClause clause = typeDefinition.getImplementsClause();
    clause.getReferenceElementsGroovy()[0].delete();
    return clause;
  }
@NotNull
  @Override
  public GrImplementsClause createImplementsClause()