code: public GroovyRowResult firstRow(Map params, String sql) throws SQLException {
          return firstRow(sql, singletonList(params));
      }
docs: A variant of {@link #firstRow(String, java.util.List)}
  useful when providing the named parameters as named arguments.
  
  @param params a map containing the named parameters
  @param sql    the SQL statement
  @return a GroovyRowResult object or <code>null</code> if no row is found
  @throws SQLException if a database access error occurs
  @since 1.8.7