stuff.rb

    private def valid_tx_type?(tx_type)                                                                             
       allowed_types = %w(query commit)                                                                              
       if allowed_types.map(&:to_sym).include?(tx_type)                                                              
         return true                                                                                                 
       else                                                                                                          
         raise ArgumentError, "tx_type must be one of the following: :#{allowed_types.join(' :')}"                   
       end                                                                                                           
     end