ValueError: invalid syntax for integer with base 10 while using adafruit_requests in Circuit Python

Question

I am trying to build a simple notification application to detect when my letter box is opened and send a notification via pushbullet using Raspberry Pico W.

This is the application:

import os
import adafruit_requests
import board
import digitalio
import time
import adafruit_debouncer
import wifi
import ssl
import os
import ipaddress
import wifi
import socketpool

quotes_url = "https://www.adafruit.com/api/quotes.php"

def connect_to_wifi():
    print("Connecting to WiFi")
    wifi.radio.connect(os.getenv('SSID'), os.getenv('PASSWORD'))
    print("Connected to WiFi")
    time.sleep(10)

def send_notification(title, message):
    api_key = os.getenv('PUSHBULLET_API_KEY')
    url = "https://api.pushbullet.com/v2/pushes"
    headers = {
        "Authorization": "Bearer " + api_key,
        "Content-Type": "application/json"
    }
    data = {
        "type": "note",
        "title": title,
        "body": message
    }
    print(headers)
    pool = socketpool.SocketPool(wifi.radio)

    requests = adafruit_requests.Session(pool, ssl.create_default_context())

    response = requests.get(quotes_url)
    print(response.content)
    response = requests.post(url, headers=headers, json=data)

    if response.status_code == 200:
        print("Notification sent successfully!")
    else:
        print("Failed to send notification.")

def blink_led():
    led = digitalio.DigitalInOut(board.LED)
    led.direction = digitalio.Direction.OUTPUT

    switch_pin = digitalio.DigitalInOut(board.GP21)
    switch_pin.direction = digitalio.Direction.INPUT
    switch_pin.pull = digitalio.Pull.UP

    switch_db = adafruit_debouncer.Debouncer(switch_pin)
    last_switch_state = False

    BLINK_ON_DURATION = 1000000000  # 1 second in nanoseconds
    BLINK_OFF_DURATION = 1000000000  # 1 second in nanoseconds
    LAST_BLINK_TIME = -1

    while True:
        switch_db.update()

        if switch_db.fell:
            LAST_BLINK_TIME = -1

        current_switch_state = switch_db.value

        if current_switch_state != last_switch_state:
            current_time = time.localtime()
            notification_time = "{}/{}/{} {}:{}:{}".format(current_time.tm_mday, current_time.tm_mon, current_time.tm_year,
                                              current_time.tm_hour, current_time.tm_min, current_time.tm_sec)
            #send_notification("Mailbox notification", notification_time + " - You (probably) got mail :)")
            send_notification("Mailbox notification", "You (probably) got mail :)")
            last_switch_state = current_switch_state

        now = time.monotonic_ns()
        if not current_switch_state and now >= LAST_BLINK_TIME + BLINK_OFF_DURATION:
            led.value = True
            LAST_BLINK_TIME = now
        if led.value and now >= LAST_BLINK_TIME + BLINK_ON_DURATION:
            led.value = False
            LAST_BLINK_TIME = now

        print("LED status:", led.value)
        print("Reed switch status:", current_switch_state)

        time.sleep(0.01)


connect_to_wifi()
blink_led()

It used to work fine but now I get:

ValueError: invalid syntax for integer with base 10

The first get request is just a test and works perfectly, the second one throws the error, here's a more complete log:

b'[{"text":"The most worth-while thing is to try to put happiness into the lives of others","author":"Robert Baden-Powell"}]'
Traceback (most recent call last):
  File "code.py", line 94, in <module>
  File "code.py", line 76, in blink_led
  File "code.py", line 41, in send_notification
  File "adafruit_requests.py", line 715, in post
  File "adafruit_requests.py", line 677, in request
  File "adafruit_requests.py", line 183, in __init__
ValueError: invalid syntax for integer with base 10

How can I solve the error?