References:
            https://developer.github.com/v3/pulls/#get-a-single-pull-request

def from_github(repo: GithubRepository,
                    pull_id: int) -> 'PullRequestDetails':
        """
        References:
            https://developer.github.com/v3/pulls/#get-a-single-pull-request
        """
        url = ("https://api.github.com/repos/{}/{}/pulls/{}"
               "?access_token={}".format(repo.organization,
                                         repo.name,
                                         pull_id,
                                         repo.access_token))

        response = requests.get(url)

        if response.status_code != 200:
            raise RuntimeError(
                'Pull check failed. Code: {}. Content: {}.'.format(
                    response.status_code, response.content))

        payload = json.JSONDecoder().decode(response.content.decode())
        return PullRequestDetails(payload, repo)