code: def EveryNCallback(self):
          
          # print('ncall ', self.n_callbacks)
          if self.do_callbacks:
              if self.n_callbacks >= self.callback_step:
                  # print('n_callbacks', self.n_callbacks)
                  for func, func_dict in self.callback_funcs:
                      func(func_dict)
                      print('func:::', func)
  
                  self.latest_callback_index +=1
                  if self.latest_callback_index >= len(self.callback_function_list):
                      # print('done with callbacks')
                      self.do_callbacks = False
                  else:
                      out = self.callback_function_list[self.latest_callback_index]
                      callback_time = out[0]
                      self.callback_step = int(callback_time/expt_settings.callback_resolution)
                      # print('updatin callback step', self.callback_step)
                      self.callback_funcs = out[1]
  
          self.n_callbacks += 1
          #print('n_callbacks', self.n_callbacks)
          return 0
docs: Called by PyDAQmx whenever a callback event occurs.