Run a python command in the enviornment context.

        :param cmd: A command to run in the environment - runs with `python -c`
        :type cmd: str or list
        :param str cwd: The working directory in which to execute the command, defaults to :data:`os.curdir`
        :return: A finished command object
        :rtype: :class:`~subprocess.Popen`

def run_py(self, cmd, cwd=os.curdir):
        """Run a python command in the enviornment context.

        :param cmd: A command to run in the environment - runs with `python -c`
        :type cmd: str or list
        :param str cwd: The working directory in which to execute the command, defaults to :data:`os.curdir`
        :return: A finished command object
        :rtype: :class:`~subprocess.Popen`
        """

        c = None
        if isinstance(cmd, six.string_types):
            script = vistir.cmdparse.Script.parse("{0} -c {1}".format(self.python, cmd))
        else:
            script = vistir.cmdparse.Script.parse([self.python, "-c"] + list(cmd))
        with self.activated():
            c = vistir.misc.run(script._parts, return_object=True, nospin=True, cwd=cwd, write_to_stdout=False)
        return c