(merge (connection_string cfg) (OC.connection_string opt_cfg))
(OC.merge_maybes (log_file cfg) (OC.log_file opt_cfg))
(merge (log_level cfg) (OC.log_level opt_cfg))
(merge (connection_string cfg) (OC.connection_string opt_cfg))
(OC.merge_maybes (log_file cfg) (OC.log_file opt_cfg))
(merge (log_level cfg) (OC.log_level opt_cfg))