sample.py contains following
    def run_cmd(self, cmd):
        self.logger.debug("Running command : %s" % cmd)
        process = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE,
                                   stderr=subprocess.PIPE)

	cmd = "source .x-venv/bin/activate; "
	run_cmd(cmd)
	call_do_something()

And sample.py is invoked as
# source .y-venv/bin/activate
will the call_do_something be executed in x-venv or y-venv.
Just to make things more complicated lets say y-venv is a python2 venv and x-venv is a python3 venv