docs: def sendPkt(self, pkt, retry=5, sleep_time=0.01):
  		"""
  		Sends a packet and waits for a return. If no return is given, then it
  		resends the packet. If an error occurs, it also resends the packet.
  
  		in:
  			pkt - command packet to send to servo
  			cnt - how many retries should this do? default = 5
  		out:
  			array of packets
  		"""
  		for cnt in range(retry):
  			self.serial.flushInput()
  			self.write(pkt)  # send packet to servo
  			ans = self.read()  # get return status packet
  
  			if ans:
  				# check for error and resend
  				return ans
  
  			else:
  				# print('>> retry {} <<'.format(cnt))
  				time.sleep(sleep_time)
  
  		return None