code: def outfiles(fmt, nfiles, progress, leave=True):
      
      if nfiles > 1:
          fnames = (fmt % i for i in range(nfiles))
      elif nfiles == 1:
          fnames = (fmt,)
      else:
          raise ValueError('output file count <= 0')
  
      if progress:
          fnames = tqdm(fnames, total=nfiles,
                        desc='Generating', unit='file',
                        bar_format=BAR_FORMAT,
                        leave=leave, dynamic_ncols=True)
  
      yield fnames
  
      if progress:
          fnames.close()
docs: Get output file paths.
  
      Parameters
      ----------
      fmt : `str`
          File path format string.
      nfiles : `int`
          Number of files.
      progress : `bool`
          Show progress bars.
      leave : `bool`, optional
          Leave progress bar (default: True).
  
      Raises
      ------
      ValueError
          If nfiles <= 0.
  
      Returns
      -------
      `generator` of `str`
          Output file paths.