code: def write_lst(self):
          
  
          ret = False
          out = ''
          system = self.system
          dae = self.system.dae
          varname = self.system.varname
          template = '{:>6g}, {:>25s}, {:>35s}\n'
  
          # header line
          out += template.format(0, 'Time [s]', '$Time\\ [s]$')
  
          # include line flow variables in algebraic variables
          nflows = 0
          if self.system.tds.config.compute_flows:
              nflows = 2 * self.system.Bus.n + \
                       8 * self.system.Line.n + \
                       2 * self.system.Area.n_combination
  
          # output variable indices
          if system.Recorder.n == 0:
              state_idx = list(range(dae.n))
              algeb_idx = list(range(dae.n, dae.n + dae.m + nflows))
              idx = state_idx + algeb_idx
          else:
              idx = system.Recorder.varout_idx
  
          # variable names concatenated
          uname = varname.unamex + varname.unamey
          fname = varname.fnamex + varname.fnamey
  
          for e, i in enumerate(idx):
              out += template.format(e + 1, uname[i], fname[i])
  
          try:
              with open(self.system.files.lst, 'w') as f:
                  f.write(out)
              ret = True
          except IOError:
              logger.error('I/O Error while writing the lst file.')
  
          return ret
docs: Dump the variable name lst file
  
          :return: succeed flag