@Nullable
public static JetModifierList replaceModifierList(
@NotNull JetModifierListOwner owner, @Nullable JetModifierList modifierList) {
JetModifierList oldModifierList = owner.getModifierList();
if (modifierList == null) {
if (oldModifierList != null) oldModifierList.delete();
return null;
} else {
if (oldModifierList == null) {
PsiElement firstChild = owner.getFirstChild();
return (JetModifierList) owner.addBefore(modifierList, firstChild);
} else {
return (JetModifierList) oldModifierList.replace(modifierList);
}
}
}
