@API(status = API.Status.STABLE)
    public <T> @NonNull Collection<T> getAll(
            final @NonNull String flag
    ) {
        final List values = this.flagValues.get(flag);
        if (values != null) {
            return Collections.unmodifiableList((List<T>) values);
        }
        return Collections.emptyList();
    }
Returns all supplied flag values for the given {@code flag}.

@param flag the flag
@param <T>  the flag value type
@return unmodifiable view of all stored flag values, or {@link Collections#emptyList()}.
cloud-core/src/main/java/org/incendo/cloud/parser/flag/FlagContext.java