final TemplateManager templateManager = TemplateManager.getInstance(project);
Template template = templateManager.createTemplate("", "");
template.setToReformat(true);
template.addTextSegment("class ");
template.addVariable(DartPresentableUtil.getExpression(myClassName), false);
template.addTextSegment("{\n");
template.addEndVariable();
template.addTextSegment("\n}\n");
final Editor openedEditor = navigate(project, anchor.getTextOffset(), anchor.getContainingFile().getVirtualFile());