code: def save_data(self, idx):
          
          for name in self:
              actual = getattr(self, name)
              diskflag = getattr(self, '_%s_diskflag' % name)
              ramflag = getattr(self, '_%s_ramflag' % name)
              if diskflag:
                  file_ = getattr(self, '_%s_file' % name)
                  ndim = getattr(self, '_%s_ndim' % name)
                  length_tot = 1
                  for jdx in range(ndim):
                      length = getattr(self, '_%s_length_%s' % (name, jdx))
                      length_tot *= length
                  if ndim:
                      raw = struct.pack(length_tot*'d', *actual.flatten())
                  else:
                      raw = struct.pack('d', actual)
                  file_.write(raw)
              elif ramflag:
                  array = getattr(self, '_%s_array' % name)
                  array[idx] = actual
docs: Save the internal data of all sequences with an activated flag.
          Write to file if the corresponding disk flag is activated; store
          in working memory if the corresponding ram flag is activated.