def files_exist(comma_sep_fps):
 filenames = comma_sep_fps.split(',')
 for file in filenames:
  if (not exists(file)):
   return False
 return True

def files_exist ( comma_sep_fps ) : filenames = comma_sep_fps . split ( ',' ) for file in filenames : if ( not exists ( file ) ) : return False return True
check if all files in commasep list exist comma_sep_fps: list of filenames as comma-separated string .