code: function(key) {
  				var self = this;
  				return this.done(function(s) {
  					if (!key)
  						return self._state;
  					var out = self._state[key];
  					return (typeof out === 'undefined') ? deep.Undefined : out;
  				});
  			}
docs: read key/value in current state
  
  @chainable
  @method state
  @param  {String} key
  @param  {*} value
  @return {deep.NodesChain} this