code: function callback(unknown) {
      // returns the cb if a cb
      // returns a noop function if undefined
      // throws an error if neither
      // -------------------------
      // assume it is a function to be returned
      var returnFunction = unknown;
      // check if it's undefined
      if (unknown === undefined) {
          // if it is, replace it with a noop function
          returnFunction = _.noop;
      // otherwise, check if it's a function
      } else if (!_.isFunction(unknown)) {
          // if not a function and not undefined, something
          // is unexpected, programmatically.
          var error = new VError("Defined object passed as a callback is not a function");
          error.object = unknown;
          throw error;
      }
      // get here if either it was a function in the first place
      // or was undefined and we defined it.  Return the function.
      return returnFunction;
  }
docs: log.info = console.error.bind(console, "info: "); log.debug = console.error.bind(console, "debug: "); [ Optional CB ]