code: @Override
      public T addPackage(String pack) throws IllegalArgumentException {
          Validate.notNull(pack, "Package must be specified");
  
          return addPackages(false, pack);
      }
docs: /*
  (non-Javadoc)
  
  @see org.jboss.shrinkwrap.api.container.ClassContainer#addPackage(java.lang.String)