code: function(method, url, date) {
          var timestamp = (date || new Date()).toISOString().replace(/\.\d+Z$/, 'Z'),
              addPubKey = this.options.user !== this.options.publicKey,
              qs = url.toString().indexOf('?') > -1 ? '&' : '?',
              signUrl = addPubKey ? url + qs + 'publicKey=' + this.options.publicKey : url,
              signature = this.generateSignature(method, signUrl.toString(), timestamp);
  
          qs = addPubKey ? '&' : qs;
          qs += 'signature=' + encodeURIComponent(signature);
          qs += '&timestamp=' + encodeURIComponent(timestamp);
  
          return signUrl + qs;
      }
docs: Get a signed version of a given URL
  
  @param  {String} method - HTTP method
  @param  {String} url    - Endpoint URL
  @param  {Date}   [date] - Date to use for signing request
  @return {String}