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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_pr(pr_num, config=None, repo=DEFAULT_REPO, raw=False):
 """ Get the payload for the given PR number. Let exceptions bubble up. """

    response = requests.get(PR_ENDPOINT.format(repo, pr_num), auth=get_auth_info(config))

    if raw:
        return response
    else:
        response.raise_for_status()
        return response.json()