private static LookupElement[] collectLookupItems(@NotNull final ScopeOwner parentScope) {
    Set<LookupElement> items = new LinkedHashSet<>();

    final Collection<String> usedNames = PyUtil.collectUsedNames(parentScope);
    for (String name : usedNames) {
      if (name != null)
        items.add(LookupElementBuilder.create(name));
    }

    return items.toArray(LookupElement.EMPTY_ARRAY);
  }
private static LookupElement[] collectLookupItems(@NotNull final ScopeOwner parentScope)