def app_start(self, package_name: str, activity: str = None):
        """start app with "am start" or "monkey" """
        if activity:
            self.shell(["am", "start", "-n", package_name + "/" + activity])
        else:
            self.shell(
                [
                    "monkey",
                    "-p",
                    package_name,
                    "-c",
                    "android.intent.category.LAUNCHER",
                    "1",
                ]
            )
start app with "am start" or "monkey" 
adbutils/shell.py