code: function(labels) {
      if (labels && !_.isArray(labels)) {
        labels = [labels]
      };
      return labels ? ':' + _.map(labels, cons.formatLabel).join(':') + ' ' : '';
    }
docs: Turn labels (single arg) into proper format for neo4j.
  @private
  @param  {string|Array} labels A single string, or an array of strings
  @return {string}        labelString
  
  @example
  cons.stringifyLabel('')
  cons.stringifyLabel(undefined)
  cons.stringifyLabel(null)
  // => ''
  
  cons.stringifyLabel('label1')
  // => ':label1 '
  
  cons.stringifyLabel(['label1', 'label2'])
  // => ':label1:label2 '