try:
    fin = open('/path/xxx.png', 'rb') 
    pic_str = base64.b64encode(fin.read())
    fin.close()
    response = sms_client.create_signature(content="百度", content_type="Enterprise",
                                           signature_file_base_64=pic_str,
                                           signature_file_format="png")
except ex.BceHttpClientError as e:
    if isinstance(e.last_error, ex.BceServerError):
        LOG.error('send request failed. Response %s, code: %s, request_id: %s'
                  % (e.last_error.status_code, e.last_error.code, e.last_error.request_id))
    else:
        LOG.error('send request failed. Unknown exception: %s' % e)

try:
    response = sms_client.get_signature_detail(signature_id)
except ex.BceHttpClientError as e:
    if isinstance(e.last_error, ex.BceServerError):
        LOG.error('send request failed. Response %s, code: %s, request_id: %s'
                  % (e.last_error.status_code, e.last_error.code, e.last_error.request_id))
    else:
        LOG.error('send request failed. Unknown exception: %s' % e)

try:
    response = sms_client.update_signature(content="BaiduSms", content_type="MobileApp", country_type="GLOBAL",
                                           signature_id=signature_id)
except ex.BceHttpClientError as e:
    if isinstance(e.last_error, ex.BceServerError):
        LOG.error('send request failed. Response %s, code: %s, request_id: %s'
                  % (e.last_error.status_code, e.last_error.code, e.last_error.request_id))
    else:
        LOG.error('send request failed. Unknown exception: %s' % e)

try:
    response = sms_client.delete_signature(signature_id)
except ex.BceHttpClientError as e:
    if isinstance(e.last_error, ex.BceServerError):
        LOG.error('send request failed. Response %s, code: %s, request_id: %s'
                  % (e.last_error.status_code, e.last_error.code, e.last_error.request_id))
    else:
        LOG.error('send request failed. Unknown exception: %s' % e)