code: public void addVariant(CmsDocumentDependency dep) {
  
          // check if already exists
          for (CmsDocumentDependency lang : m_variants) {
              if (lang.getLocale().equals(dep.getLocale())) {
                  return;
              }
          }
          dep.setType(DependencyType.variant);
          m_variants.add(dep);
          addDependency(dep);
      }
docs: Adds another language version document dependency to this document.<p>
  
  @param dep the language version document dependency to add