presto-parser/src/main/java/io/prestosql/sql/tree/Isolation.java/Isolation/equals
class Isolation:    @Override
    public boolean equals(Object obj)
    {
        if (this == obj) {
            return true;
        }
        if (obj == null || getClass() != obj.getClass()) {
            return false;
        }
        final Isolation other = (Isolation) obj;
        return this.level == other.level;
    }