code: def tidy(fnames):
      
      for fname in fnames:
          try:
              node = nrml.read(fname)
          except ValueError as err:
              print(err)
              return
          with open(fname + '.bak', 'wb') as f:
              f.write(open(fname, 'rb').read())
          with open(fname, 'wb') as f:
              # make sure the xmlns i.e. the NRML version is unchanged
              nrml.write(node.nodes, f, writers.FIVEDIGITS, xmlns=node['xmlns'])
          print('Reformatted %s, original left in %s.bak' % (fname, fname))
docs: Reformat a NRML file in a canonical form. That also means reducing the
      precision of the floats to a standard value. If the file is invalid,
      a clear error message is shown.