curl --location --request POST 'https://api.qugongbao.com/gst-api/api/qgb/customer/customerSign' \
--header 'Content-Type: application/json' \
--data-raw '{
"custNo": "string",
"contractNo": "string",
"spCode": "string",
"returnUrl": "string",
"notifyUrl": "string"
}'{
"contractUrl": "string"
}