https://docs.cloud.google.com/java/docs/reference/google-cloud-compute/latest/com.google.cloud.compute.v1.VpnGateway.GatewayIpVersion
Enum VpnGateway.GatewayIpVersion (1.101.0) | Java client libraries | Google Cloud Documentation
https://docs.cloud.google.com/python/docs/reference/google-cloud-compute-v1beta/latest/google.cloud.compute_v1beta.types.VpnGateway.GatewayIpVersion
Class GatewayIpVersion (0.11.0) | Python client libraries | Google Cloud Documentation
python clientgoogle cloudclasslibrariesdocumentation