void (@NotNull Project project, PsiElement @NotNull [] elements, DataContext dataContext) { if (elements.length != 1) return; final PsiElement targetMember = findTargetMember(elements[0]); if (targetMember == null) return; final ChangeSignatureHandler handler = getChangeSignatureHandler(targetMember); if (handler == null) return; handler.invoke(project, new PsiElement[]{targetMember}, dataContext); }