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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 epost(database, ids: List[str], webenv=False, api_key=False, email=False, **kwargs) -> Optional[EpostResult]: """Post IDs using the Entrez ESearch API. Parameters database : str Entez database to search. ids : list List of IDs to submit to the server. webenv : str An Entrez WebEnv to post ids to. api_key : str A users API key which allows more requests per second email : str A users email which is required if not using API. Returns ------- requests.Response """

    url = BASE_URL + f'epost.fcgi'
    id = ','.join(ids)
    url_params = f'db={database}&id={id}'
    url_params = check_webenv(webenv, url_params)
    url_params = check_api_key(api_key, url_params)
    url_params = check_email(email, url_params)
    resp = entrez_try_put_multiple_times(url, url_params, num_tries=3)
    time.sleep(.5)
    return parse_epost(resp.text)