def METHOD_NAME(api_key, secret_key):
    """
    Gererate an access token.
    """
    payload = ""
    headers = {"Content-Type": "application/json", "Accept": "application/json"}
    token_host = f"https://aip.baidubce.com/oauth/2.0/token?grant_type=client_credentials&client_id={api_key}&client_secret={secret_key}"
    response = requests.request("POST", token_host, headers=headers, data=payload)
    if response:
        res = response.json()
    else:
        raise RuntimeError("Request access token error.")
    return res["access_token"]