code: def add_element(self, element):
          
          element = element_resolver(element)
  
          self.make_request(
              ModificationFailed,
              method='create',
              resource='category_add_element',
              json={'value': element})
docs: Element can be href or type :py:class:`smc.base.model.Element`
          ::
  
              >>> from smc.elements.other import Category
              >>> category = Category('foo')
              >>> category.add_element(Host('kali'))
  
          :param str,Element element: element to add to tag
          :raises: ModificationFailed: failed adding element
          :return: None