docs: function(first, second) {
      // the basic building block of the yes/no chaining system. agree(f1,
      // f2) generates a new function which returns the boolean results of
      // both of the passed functions to a single logical-anded result. If
      // either are not passed, the other is used exclusively.
      if (!first) {
        return second;
      }
      if (!second) {
        return first;
      }
  
      return function() {
        return first.apply(window, arguments) && second.apply(window, arguments);
      }
    }