Find a praticular blink(1) device, or the first one
        :param serial_number: serial number of blink(1) device (from Blink1.list())

def find(serial_number=None):
        """
        Find a praticular blink(1) device, or the first one
        :param serial_number: serial number of blink(1) device (from Blink1.list())
        """
        try:
            hidraw = hid.device(VENDOR_ID,PRODUCT_ID,serial_number)
            hidraw.open(VENDOR_ID,PRODUCT_ID,serial_number)
            # hidraw = hid.device(VENDOR_ID,PRODUCT_ID,unicode(serial_number))
            # hidraw.open(VENDOR_ID,PRODUCT_ID,unicode(serial_number))
        except IOError as e:  # python2
            raise Blink1ConnectionFailed(e)
            hidraw = None
        except OSError as e:  # python3
            raise Blink1ConnectionFailed(e)
            hidraw = None

        return hidraw