[Python] Adafruit nrf52840 loops program

I'm using Adafruit "BLE HID Keyboard Buttons" tutorial : I wanted to use arrows in order to navigate in the window with accessibility->access control on an iPad but as soon as I get connected to bluetooth, the characters defined for the five buttons display in a repetitive sequence in any text field I open (browser, note app ...etc.). How can I stop this repetitive sequence in order to use the five buttons only when I press on any of the five buttons? I didn't see any loop in the script (I just fiddle with programming)

#This example acts as a BLE HID keyboard to peer devices.
#Attach five buttons with pullup resistors to Feather nRF52840
#each button will send a configurable keycode to mobile device or computer

import time
import board
from digitalio import DigitalInOut, Direction

import adafruit_ble
from adafruit_ble.advertising import Advertisement
from adafruit_ble.advertising.standard import ProvideServicesAdvertisement
from adafruit_ble.services.standard.hid import HIDService
from adafruit_ble.services.standard.device_info import DeviceInfoService
from adafruit_hid.keyboard import Keyboard
from adafruit_hid.keyboard_layout_us import KeyboardLayoutUS
from adafruit_hid.keycode import Keycode

button_1 = DigitalInOut(board.D11)
button_2 = DigitalInOut(board.D10)
button_3 = DigitalInOut(board.D9)
button_4 = DigitalInOut(board.D6)
button_5 = DigitalInOut(board.D5)

button_1.direction = Direction.INPUT
button_2.direction = Direction.INPUT
button_3.direction = Direction.INPUT
button_4.direction = Direction.INPUT
button_5.direction = Direction.INPUT

hid = HIDService()

device_info = DeviceInfoService(software_revision=adafruit_ble.__version__,
manufacturer="Adafruit Industries")
advertisement = ProvideServicesAdvertisement(hid)
advertisement.appearance = 961
scan_response = Advertisement()
scan_response.complete_name = "CircuitPython HID"

ble = adafruit_ble.BLERadio()
if not ble.connected:
print("advertising")
ble.start_advertising(advertisement, scan_response)
else:
print("already connected")
print(ble.connections)

k = Keyboard(hid.devices)
kl = KeyboardLayoutUS(k)
while True:
while not ble.connected:
pass
print("Start typing:")

while ble.connected:
if not button_1.value: # pull up logic means button low when pressed
k.send(Keycode.DOWN_ARROW)
time.sleep(0.4)

if not button_2.value:
k.send(Keycode.LEFT_ARROW)
time.sleep(0.4)

if not button_3.value:
k.send(Keycode.UP_ARROW)
time.sleep(0.4)

if not button_4.value:
k.send(Keycode.RIGHT_ARROW)
time.sleep(0.4)

if not button_5.value:
k.send(Keycode.ENTER)
time.sleep(0.4)

ble.start_advertising(advertisement)

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