         if error
           callback and callback error
         else
-          result._id = @collection.insert _.clone result
+          result._id = self.collection.insert _.clone result
           callback and callback null, result
       
       return @

      @storagePath       = @storagePath.replace /\/$/, ''
      @storagePath       = nodePath.normalize @storagePath

      fs.mkdirsSync @storagePath

      check @strict, Boolean
      check @throttle, Match.OneOf false, Number


      {extension, extensionWithDot} = @getExt fileName

      self      = @
      path      = "#{@storagePath}/#{randFileName}#{extensionWithDot}"
      
      opts.type = @getMimeType opts
