Breakpoint success outside on_message. Breakpoint failure in on_message method

import frida
def on_message(message, data):
    if message['type'] == 'send': # PyCharm breakpoint failed, pdb breakpoint success
        print('1 message')
    else:
        print('2')

# breakpoint success
jscode = 'Java.perform(function () { send("test") }); '
device = frida.get_usb_device()
app = device.get_frontmost_application()
session = device.attach(app.pid)
script = session.create_script(jscode)
script.on('message', on_message)
script.load()