gistfile1.py

ids = set()
with gzip.open(ids_file, 'rt') as idsf:                                                                                                                    
    for id in idsf:                                                                                                                                        
        # Be careful to always stip the newline character at the end                                                                                       
        ids.add(id.strip())

gistfile2.scala

val ids = Resource.fromInputStream(new GZIPInputStream(new FileInputStream(locationIdsFile))).lines().toSet