Getting 400 Bad Request when trying to create security policy rule

[DeepSpace]

I'm trying to create a security policy rule using the REST API but I keep getting an empty response with 400 status.

URL:

https://<PANORAMA_IP>/restapi/9.0/Policies/SecurityPreRules

Headers:

Content-Type: application/json
X-PAN-KEY: <KEY>

{
	"entry": [{
		"target": {
			"devices": [{
				"@name": "001801020796",
				"vsys": {
					"entry": [{
						"@name": "vsys5"
					}]
				}
			}]
		},
		"source": {
			"member": ["1.1.1.1"]
		},
		"destination": {
			"member": ["2.2.2.2"]
		},
		"service": {
			"member": ["TCP_18207"]
		},
		"action": "allow",
		"@name": "new-rule-1",
		"@location": "device-group",
		"@device-group": "ST_DG1.1.1.1",
		"to": {
			"member": ["any"]
		},
		"from": {
			"member": ["any"]
		},
		"application": {
			"member": ["any"]
		}
	}]
}

I also tried adding ?location=device-group&device-group=ST_DG1.1.1.1 to the URL but it did not make any change.

I'm getting back an empty response with status code 400. I tried to find it in https://<PANORAMA_IP>/debug but it wasn't logged.

My end goal is to create a policy rule that contains a specific vsys of a specific firewall as "target". I'm using the panos Python library and for now there seems to be a bug with this functionality (https://github.com/PaloAltoNetworks/pan-os-python/issues/273) so I resorted to making direct API calls.