def get_submission(self, user, **kwargs):
user_id = obj_or_id(user, "<STR_LIT:user>", (User,))<EOL>response = self._requester.request(<EOL>'<STR_LIT:GET>',<EOL>'<STR_LIT>'.format(self.course_id, self.id, user_id),<EOL>_kwargs=combine_kwargs(**kwargs)<EOL>)<EOL>response_json = response.json()<EOL>response_json.update(course_id=self.course_id)<EOL>return Submission(self._requester, response_json)<EOL>
Get a single submission, based on user id.

:calls: `GET /api/v1/courses/:course_id/assignments/:assignment_id/submissions/:user_id \
<https://canvas.instructure.com/doc/api/submissions.html#method.submissions_api.show>`_

:param user: The object or ID of the related user
:type user: :class:`canvasapi.user.User` or int

:rtype: :class:`canvasapi.submission.Submission`