public final void extend(@Nullable CompletionType type,
                           final @NotNull ElementPattern<? extends PsiElement> place, CompletionProvider<CompletionParameters> provider) {
    myMap.putValue(type, new Pair<>(place, provider));
  }
public final void extend(@Nullable CompletionType type,
                           final @NotNull ElementPattern<? extends PsiElement> place, CompletionProvider<CompletionParameters> provider)