code: def create(cls, name, sandbox_data_center, portal_username=None, comment=None):
          
          json = {
              'name': name,
              'sandbox_data_center': element_resolver(sandbox_data_center),
              'portal_username': portal_username if portal_username else '',
              'comment': comment}
          return ElementCreator(cls, json)
docs: Create a Sandbox Service element