Permission to create gateway object from API

What is the permission required for API to create a gateway object?

I have created a role using custom mode so I can remove the excessive privilege later, and I have assigned all the possible privilege with write permission. I am still getting run time error when creating a simple gateway object from ansible. It works find if the role is given full write permission. 

Error message below:

fatal: [127.0.0.1]: FAILED! => {"changed": false, "failed": true, "msg": "Command 'add-simple-gateway {u'one-time-password': u'aaa12345', u'interfaces': [{u'ipv4-network-mask': u'255.255.255.0', u'anti-spoofing': u'true', u'ipv4-address': u'10.0.1.88', u'name': u'eth0', u'topology': u'External'}, {u'anti-spoofing': u'true', u'name': u'eth1', u'topology-settings': {u'ip-address-behind-this-interface': u'network defined by the interface ip and net mask'}, u'ipv4-network-mask': u'255.255.255.0', u'ipv4-address': u'172.16.1.88', u'topology': u'Internal'}], u'name': u'demo_gateway', u'ip-address': u'192.0.1.88', u'comments': u'added by Ansible'}' failed with error message: Runtime error: Error reading XMLStreamReader: Unexpected EOF in prolog at javax.xml.stream.SerializableLocation@c1137a34. All changes are discarded and the session is invalidated."}