public DeleteStackInstancesRequest withRegions(String... regions) {
        if (this.regions == null) {
            setRegions(new com.amazonaws.internal.SdkInternalList<String>(regions.length));
        }
        for (String ele : regions) {
            this.regions.add(ele);
        }
        return this;
    }
<p>
The Amazon Web Services Regions where you want to delete stack set instances.
</p>
<p>
<b>NOTE:</b> This method appends the values to the existing list (if any). Use
{@link #setRegions(java.util.Collection)} or {@link #withRegions(java.util.Collection)} if you want to override
the existing values.
</p>

@param regions
       The Amazon Web Services Regions where you want to delete stack set instances.
@return Returns a reference to this object so that method calls can be chained together.
aws-java-sdk-cloudformation/src/main/java/com/amazonaws/services/cloudformation/model/DeleteStackInstancesRequest.java