code: function(definition) {
  				_assert(
  					definition.name != null,
  					"extensions must have a `name` property."
  				);
  				_assert(
  					definition.version != null,
  					"extensions must have a `version` property."
  				);
  				$.ui.fancytree._extensions[definition.name] = definition;
  			}
docs: Add Fancytree extension definition to the list of globally available extensions.
  
  @param {object} definition