Custom domain plug-in classes may implement utility methods to support the implementation of the main interface methods. An example is the _pad method shown in Custom Sorting. To avoid inadvertently overriding another inherited method, or using a method name that conflicts with a method introduced in a later Cúram release, you should prefix such utility methods with an underscore character as shown. Underscore characters will not be used in the client infrastructure, so they will guarantee that no naming conflict will arise in the future. For similar reasons, do not create classes in packages that might conflict with Cúram package names. All Cúram packages begin with "curam", so avoiding that name is sufficient. The examples in this chapter used the package name prefix "custom", but this is not a requirement.