Permissions
Permissions are handled in the base Connector()._set_interfaces_permissions() in switches/connect/connector.py around line 1758
_set_interfaces_permissions() is called from Connector.get_basic_info() after interfaces have been loaded (around line 358)
This function loops through all the interfaces found above. It sets permissions as needed. And, it calls self._can_manage_interface() which by default returns False.
Drivers can overload _can_manage_interface() to implement specific use-cases to disable management on stacking interfaces, etc. See switches/connect/snmp/comware/connector.py around line 387 for an example.
Note
A driver should NOT override the base _set_interfaces_permissions(), rather it should implement _can_manage_interface() as needed!