presto-parquet/src/main/java/io/prestosql/parquet/dictionary/Dictionary.java/Dictionary/Dictionary
class Dictionary:    public Dictionary(ParquetEncoding encoding)
    {
        checkArgument(
                encoding == ParquetEncoding.PLAIN_DICTIONARY || encoding == ParquetEncoding.PLAIN,
                "Dictionary does not support encoding: %s",
                encoding);
    }