code: def init_app(self, app):
          
          self.init_config(app)
          app.extensions['invenio-github'] = self
  
          @app.before_first_request
          def connect_signals():
              """Connect OAuthClient signals."""
              from invenio_oauthclient.models import RemoteAccount
              from invenio_oauthclient.signals import account_setup_committed
  
              from .api import GitHubAPI
              from .handlers import account_post_init
  
              account_setup_committed.connect(
                  account_post_init,
                  sender=GitHubAPI.remote._get_current_object()
              )
  
              @event.listens_for(RemoteAccount, 'before_delete')
              def receive_before_delete(mapper, connection, target):
                  """Listen for the 'before_delete' event."""
docs: Flask application initialization.