load a url body into a manifest

def _load_manifest_from_url(manifest, url, verify_certificate=True, username=None, password=None):
    """ load a url body into a manifest """
    try:
        if username and password:
            manifest_file_handler = StringIO(lib.authenticated_get(username, password, url,
                                                                   verify=verify_certificate).decode("utf-8"))
        else:
            manifest_file_handler = StringIO(lib.cleaned_request(
                'get', url, verify=verify_certificate
            ).text)
        manifest.readfp(manifest_file_handler)
    except requests.exceptions.RequestException:
        logger.debug("", exc_info=True)
        error_message = sys.exc_info()[1]
        raise ManifestException("There was an error retrieving {0}!\n {1}".format(url, str(error_message)))