anchor.diff:  
         databases = mkOption {
           default = [];
  +        type = types.listOf types.str;
           description = ''
             List of database names to dump.
           '';
         };
   
         location = mkOption {
  +        type = types.path;
           default = "/var/backup/mysql";
           description = ''
             Location to put the gzipped MySQL database dumps.
  
positive.code: 
        singleTransaction = mkOption {
          default = false;
          description = ''
            Whether to create database dump in a single transaction
          '';
  
negative.code:       };
  
        user = mkOption {
          type = types.str;
          default = defaultUser;
          description = ''
            User to be used to perform backup.
  