I checked some of the scenarios where basename function giving empty result.
from cleanco import basename
print("Base name name for {} : {}".format('IKS APS', basename("IKS APS")))
print("Base name name for {} : {}".format('S.C.S & COMPANY', basename("S.C.S & COMPANY")))
print("Base name name for {} : {}".format('COOP', basename("COOP")))