docs: function(name, fn) {
      // Init options.
      var opts = {
        name: name,
        methods: {}
      };
      _.each(methodNames, function(methodName) {
        opts.methods[methodName] = function() {
          throw new Error('Method not implemented : ' + methodName);
        };
      });
      // Give options to callback function for decoration.
      fn(opts);
      // Return options.
      return opts;
    }