code: def add(self, data):
          
          if self.is_none or self.is_any:
              self.clear()
              self.data[self.typeof] = []
  
          try:
              self.get(self.typeof).append(element_resolver(data))
          except ElementNotFound:
              pass
docs: Add a single entry to field.
  
          Entries can be added to a rule using the href of the element
          or by loading the element directly. Element should be of type
          :py:mod:`smc.elements.network`.
          After modifying rule, call :py:meth:`~.save`.
  
          Example of adding entry by element::
  
              policy = FirewallPolicy('policy')
              for rule in policy.fw_ipv4_nat_rules.all():
                  if rule.name == 'therule':
                      rule.sources.add(Host('myhost'))
                      rule.save()
  
          .. note:: If submitting type Element and the element cannot be
                    found, it will be skipped.
  
          :param data: entry to add
          :type data: Element or str