public EntityReference withUnspecified(Boolean unspecified) {
        setUnspecified(unspecified);
        return this;
    }
<p>
Used to indicate that a principal or resource is not specified. This can be used to search for policies that are
not associated with a specific principal or resource.
</p>

@param unspecified
       Used to indicate that a principal or resource is not specified. This can be used to search for policies
       that are not associated with a specific principal or resource.
@return Returns a reference to this object so that method calls can be chained together.
aws-java-sdk-verifiedpermissions/src/main/java/com/amazonaws/services/verifiedpermissions/model/EntityReference.java