docs: def read_register(self, addr, numBytes):
          """Reads @numBytes bytes from the grizzly starting at @addr. Due
          to packet format, cannot read more than 127 packets at a time.
          Returns a byte array of the requested data in little endian.
          @addr should be from the Addr class e.g. Addr.Speed"""
          assert numBytes <= 0x7f, "Cannot read more than 127 bytes at a time"
          cmd = chr(addr) + chr(numBytes)
          cmd += (16 - len(cmd)) * chr(0)
          return self._dev.exchange_bytes(cmd)