def is_isonet_vif(vif):
nicira_iface_id = vif.record.get('<STR_LIT>').get('<STR_LIT>')<EOL>if nicira_iface_id:<EOL><INDENT>return True<EOL><DEDENT>return False<EOL>
Determine if a vif is on isonet

    Returns True if a vif belongs to an isolated network by checking
    for a nicira interface id.