Fix Linode interfaces property (#604)

* Rename `interfaces` property to `linode_interfaces`

* Return `None` when interface generation is not `linode`

* Update docstring

* Fix test

* Use enum

Author: zliang-akamai

linode_api4/objects/linode.py

@@ -2006,15 +2006,18 @@ def interfaces_settings(self) -> LinodeInterfacesSettings:
         return self._interfaces_settings
 
     @property
-    def interfaces(self) -> List[LinodeInterface]:
+    def linode_interfaces(self) -> Optional[list[LinodeInterface]]:
         """
         All interfaces for this Linode.
 
         API Documentation: https://techdocs.akamai.com/linode-api/reference/get-linode-interface
 
-        :returns: An ordered list of interfaces under this Linode.
+        :returns: An ordered list of linode interfaces under this Linode. If the linode is with legacy config interfaces, returns None.
+        :rtype: Optional[list[LinodeInterface]]
         """
 
+        if self.interface_generation != InterfaceGeneration.LINODE:
+            return None
         if not hasattr(self, "_interfaces"):
             result = self._client.get(
                 "{}/interfaces".format(Instance.api_endpoint),

test/unit/objects/linode_test.py

@@ -481,7 +481,7 @@ def test_get_interfaces(self):
 
         assert instance.interface_generation == InterfaceGeneration.LINODE
 
-        interfaces = instance.interfaces
+        interfaces = instance.linode_interfaces
 
         LinodeInterfaceTest.assert_linode_124_interface_123(
             next(iface for iface in interfaces if iface.id == 123)