code: def start(self):
          
  
          # this shouldn't actually be possible still...
          if self.aitask is not None:
              self.stop()
              raise Exception("FIX ME : NESTED START OPERATIONS ALLOWED")
  
          self.daq_lock.acquire()
  
          self.ngenerated = 0
          self.nacquired = 0
  
          return self.reset()
docs: Writes output buffer and settings to device
  
          :returns: numpy.ndarray -- if the first presentation of a novel stimulus, or None if a repeat stimulus