docs: def write_output_files(self):
          """
          The total hydrogen bond count per frame is provided as CSV output file.
          Each trajectory has a separate file.
          """
          os.mkdir("analysis")
          os.chdir("analysis")
          os.mkdir("hydrogen_bonds")
          os.chdir("hydrogen_bonds")
          for traj in range(len(self.trajectory)):
              with open('hbonds_data_total_'+str(traj)+'.csv', 'wb') as outfile:
                  hwriter = csv.writer(outfile, delimiter=' ')
                  for time in self.hbonds_by_time[traj]:
                      hwriter.writerow([time[0],time[1]])
              for bond in self.hbonds_by_type[traj]:
                  if bond["donor_resnm"]=="LIG" and (bond["acceptor_idx"],bond["donor_idx"]) in [(k[0],k[3]) for k,v in self.hbonds_for_drawing.items()]:
                      with open('hbond_'+bond["acceptor_resnm"]+"_"+str(bond["acceptor_resid"])+"_"+bond["donor_atom"]+"_"+str(traj)+".csv","wb") as outfile:
                          hwriter = csv.writer(outfile, delimiter=' ')
                          for time in self.hbonds_timesteps[traj]:
                              result = [1 if x[0]==time and x["acceptor_idx"]==bond["acceptor_idx"] else 0 for x in self.hbonds[traj]][0]
                              hwriter.writerow([time,result])
                  if bond["donor_resnm"]!="LIG" and (bond["donor_idx"],bond["acceptor_idx"]) in [(k[0],k[3]) for k,v in self.hbonds_for_drawing.items()]:
                      with open('hbond_'+bond["donor_resnm"]+"_"+str(bond["donor_resid"])+"_"+bond["acceptor_atom"]+"_"+str(traj)+".csv","wb") as outfile:
                          hwriter = csv.writer(outfile, delimiter=' ')
                          for time in self.hbonds_timesteps[traj]:
                              result = [1 if x[0]==time and x["donor_idx"]==bond["donor_idx"] else 0 for x in self.hbonds[traj]][0]
                              hwriter.writerow([time,result])
          os.chdir("../../")