presto-memory/src/main/java/io/prestosql/plugin/memory/MemoryMetadata.java/MemoryMetadata/listViews
class MemoryMetadata:    @Override
    public synchronized List<SchemaTableName> listViews(ConnectorSession session, Optional<String> schemaName)
    {
        return views.keySet().stream()
                .filter(viewName -> schemaName.map(viewName.getSchemaName()::equals).orElse(true))
                .collect(toImmutableList());
    }