code: def is_isonet_vif(vif):
      
      nicira_iface_id = vif.record.get('other_config').get('nicira-iface-id')
  
      if nicira_iface_id:
          return True
  
      return False
docs: Determine if a vif is on isonet
  
      Returns True if a vif belongs to an isolated network by checking
      for a nicira interface id.