import glob, os 
def all_files(pattern, search_path, pathsep = os.pathsep): 
  for path in search_path.split(pathsep): 
    for match in glob.glob(os.path.join(path, pattern)): 
      yield match 
print(type(all_files('*.s', 'd:\\pm\\pm')))      
print(all_files('*.s', 'd:\\pm\\pm').__next__()) 
for match in all_files('*.s', 'd:\\pm\\pm'):   
  print(match)