class VirtualEnvironment(object):
    def __init__(self, path):
        super(VirtualEnvironment, self).__init__()

        self.path = path

    @classmethod
    def command_method(cls, environment_path):
        """"""
        environment_scripts_path = os.path.join(environment_path, "Scripts")
        environment_activate_batch = os.path.join(environment_scripts_path, "activate.bat")
        environment_deactivate_batch = os.path.join(environment_scripts_path, "deactivate.bat")

        def deco(func):
            def wrapper(*args, **kwargs):
                if os.path.exists(environment_activate_batch):

                    command_string = environment_activate_batch
                    command_string += " && {} ".format(func())
                    command_string += " && {} ".format(environment_deactivate_batch)

                    process = subprocess.Popen(command_string, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=False)

                    cache = list()
                    while True:
                        # pkg_info = dict()
                        output = process.stdout.readline()
                        if output == '' and process.poll() is not None:
                            break
                        if output:
                            output_ = output.strip()
                            print output

                    return cache
            return wrapper
        return deco

    def run_command(self, command):
        @VirtualEnvironment.command_method(self.path)
        def runner():
            return command

        runner()


venv = VirtualEnvironment("E:\\my_venv_path")
venv.run_command("pip list --format json")