"""

Implement LifespanHandler.OnBeforeClose to execute custom

code before browser window closes.

"""

from cefpython3 import cefpython as cef

def main():

cef.Initialize()

browser = cef.CreateBrowserSync(url="https://www.google.com/",

window_title="OnBeforeClose")

browser.SetClientHandler(LifespanHandler())

cef.MessageLoop()

del browser

cef.Shutdown()

class LifespanHandler(object):

def OnBeforeClose(self, browser):

print("Browser ID: {}".format(browser.GetIdentifier()))

print("Browser will close and app will exit")

if __name__ == '__main__':

main()