presto-parser/src/main/java/io/prestosql/sql/SqlFormatter.java/SqlFormatter/visitRevokeRoles
class SqlFormatter:        @Override
        protected Void visitRevokeRoles(RevokeRoles node, Integer context)
        {
            builder.append("REVOKE ");
            if (node.isAdminOptionFor()) {
                builder.append("ADMIN OPTION FOR ");
            }
            builder.append(node.getRoles().stream()
                    .map(Identifier::toString)
                    .collect(joining(", ")));
            builder.append(" FROM ");
            builder.append(node.getGrantees().stream()
                    .map(Formatter::formatPrincipal)
                    .collect(joining(", ")));
            if (node.getGrantor().isPresent()) {
                builder.append(" GRANTED BY ").append(formatGrantor(node.getGrantor().get()));
            }
            return null;
        }