Jac/createextracts bug (#1026)

 fix xml generation for items

Author: jacalata

tableauserverclient/server/request_factory.py

@@ -887,7 +887,6 @@ def _generate_xml(
             views_element = ET.SubElement(workbook_element, "views")
             for view_name in workbook_item.hidden_views:
                 _add_hiddenview_element(views_element, view_name)
-
         return ET.tostring(xml_request)
 
     def update_req(self, workbook_item):
@@ -960,9 +959,9 @@ def embedded_extract_req(self, xml_request, include_all=True, datasources=None):
         list_element = ET.SubElement(xml_request, "datasources")
         if include_all:
             list_element.attrib["includeAll"] = "true"
-        else:
+        elif datasources:
             for datasource_item in datasources:
-                datasource_element = list_element.SubElement(xml_request, "datasource")
+                datasource_element = ET.SubElement(list_element, "datasource")
                 datasource_element.attrib["id"] = datasource_item.id