addBasakFeathersForSubd

import pymel.core as pm

def addBasakFeathersForSubd():
    
    # find basak feathersShapes
    hair = pm.ls('CHR_basak_*_RENDER:mod_GRP:feather_hair_GRP')[0]
    neck = pm.ls('CHR_basak_*_RENDER:mod_GRP:feather_neck_GRP')[0]
    hairF = [i.getShape() for i in hair.getChildren()]
    neckF = [i.getShape() for i in neck.getChildren()]
    if not hairF or not neckF:
        pm.error('Missing Basak feathers')
    allF = hairF + neckF
    # find the rsParam
    rsMeshP = pm.ls('rsSubdiv_SET')[0]
    if not rsMeshP:
        pm.error('NO RShift meshParameters found')
    # add feathers to set
    for item in allF:
        pm.select(item, r = True)
        pm.sets( rsMeshP,forceElement = True )
        
addBasakFeathersForSubd()