presto-main/src/main/java/io/prestosql/sql/SqlPathElement.java/SqlPathElement/SqlPathElement
class SqlPathElement:    @JsonCreator
    public SqlPathElement(
            @JsonProperty("catalog") Optional<Identifier> catalog,
            @JsonProperty("schema") Identifier schema)
    {
        this.catalog = requireNonNull(catalog, "catalog is null");
        this.schema = requireNonNull(schema, "schema is null");
    }