code: function(awsResponseXml) {
                      var parser = new DOMParser(),
                          parsedDoc = parser.parseFromString(awsResponseXml, "application/xml"),
                          errorEls = parsedDoc.getElementsByTagName("Error"),
                          errorDetails = {},
                          codeEls, messageEls;
  
                      if (errorEls.length) {
                          codeEls = parsedDoc.getElementsByTagName("Code");
                          messageEls = parsedDoc.getElementsByTagName("Message");
  
                          if (messageEls.length) {
                              errorDetails.message = messageEls[0].textContent;
                          }
  
                          if (codeEls.length) {
                              errorDetails.code = codeEls[0].textContent;
                          }
  
                          return errorDetails;
                      }
                  }
docs: This parses an XML response by extracting the "Message" and "Code" elements that accompany AWS error responses.
  
  @param awsResponseXml XML response from AWS
  @returns {object} Object w/ `code` and `message` properties, or undefined if we couldn't find error info in the XML document.