demo/amd/rjs/output/unified/marionette-build.js
function(regionConfig, DefaultRegionClass) {
      var RegionClass = regionConfig.regionClass || DefaultRegionClass;
      var options = _.omit(regionConfig, 'selector', 'regionClass');
  
      if (regionConfig.selector && !options.el) {
        options.el = regionConfig.selector;
      }
  
      return new RegionClass(options);
    }
function(regionConfig, DefaultRegionClass) {
      var RegionClass = regionConfig.regionClass || DefaultRegionClass;
      var options = _.omit(regionConfig, 'selector', 'regionClass');
  
      if (regionConfig.selector && !options.el) {
        options.el = regionConfig.selector;
      }
  
      return new RegionClass(options);
    }
Build the region from a configuration object ```js { selector: '#foo', regionClass: FooRegion, allowMissingEl: false } ```