code: def _merge_out_from_infiles(in_files):
      
      fname = os.path.commonprefix([os.path.basename(f) for f in in_files])
      while fname.endswith(("-", "_", ".")):
          fname = fname[:-1]
      ext = os.path.splitext(in_files[0])[-1]
      dirname = os.path.dirname(in_files[0])
      while dirname.endswith(("split", "merge")):
          dirname = os.path.dirname(dirname)
      return os.path.join(dirname, "%s%s" % (fname, ext))
docs: Generate output merged file name from set of input files.
  
      Handles non-shared filesystems where we don't know output path when setting
      up split parts.