code: function(context) {
          var node = this.createElementDefaultNS("Extension");
          
          var bounds = context.maxExtent;
          var maxExtent = this.createElementNS(
              this.namespaces.ol, "ol:maxExtent"
          );
          this.setAttributes(maxExtent, {
              minx: bounds.left.toPrecision(18),
              miny: bounds.bottom.toPrecision(18),
              maxx: bounds.right.toPrecision(18),
              maxy: bounds.top.toPrecision(18)
          });
          node.appendChild(maxExtent);
          
          if (context.tileSize && !context.singleTile) {
              var size = this.createElementNS(
                  this.namespaces.ol, "ol:tileSize"
              );
              this.setAttributes(size, context.tileSize);
              node.appendChild(size);
          }
          
          var properties = [
              "transparent", "numZoomLevels", "units", "isBaseLayer",
              "opacity", "displayInLayerSwitcher", "singleTile"
          ];
          var child;
          for(var i=0, len=properties.length; i<len; ++i) {
              child = this.createOLPropertyNode(context, properties[i]);
              if(child) {
                  node.appendChild(child);
              }
          }
  
          return node;
      }
docs: Method: write_wmc_LayerExtension
  Add OpenLayers specific layer parameters to an Extension element.
  
  Parameters:
  context - {Object} A layer context object.
  
  Returns:
  {Element} A WMC Extension element (for a layer).