public Cluster clearSubnetMappingEntries() {
        this.subnetMapping = null;
        return this;
    }
Removes all the entries added into SubnetMapping.

@return Returns a reference to this object so that method calls can be chained together.
aws-java-sdk-cloudhsmv2/src/main/java/com/amazonaws/services/cloudhsmv2/model/Cluster.java