docs: def load_and_save_resfile(filename, outfile=None, outdir=None, mass=1.00):
      """Load a raw data file and save it as cellpy-file.
  
      Args:
          mass (float): active material mass [mg].
          outdir (path): optional, path to directory for saving the hdf5-file.
          outfile (str): optional, name of hdf5-file.
          filename (str): name of the resfile.
  
      Returns:
          out_file_name (str): name of saved file.
      """
      d = CellpyData()
  
      if not outdir:
          outdir = prms.Paths["cellpydatadir"]
  
      if not outfile:
          outfile = os.path.basename(filename).split(".")[0] + ".h5"
          outfile = os.path.join(outdir, outfile)
  
      print("filename:", filename)
      print("outfile:", outfile)
      print("outdir:", outdir)
      print("mass:", mass, "mg")
  
      d.from_raw(filename)
      d.set_mass(mass)
      d.make_step_table()
      d.make_summary()
      d.save(filename=outfile)
      d.to_csv(datadir=outdir, cycles=True, raw=True, summary=True)
      return outfile