code: @Nonnull
    @ReturnsMutableCopy
    public static final <T extends AbstractSingleton> ICommonsList <T> getAllSingletons (@Nullable final IScope aScope,
                                                                                         @Nonnull final Class <T> aDesiredClass)
    {
      ValueEnforcer.notNull (aDesiredClass, "DesiredClass");
  
      final ICommonsList <T> ret = new CommonsArrayList <> ();
      if (aScope != null)
        for (final Object aScopeValue : aScope.attrs ().values ())
          if (aScopeValue != null && aDesiredClass.isAssignableFrom (aScopeValue.getClass ()))
            ret.add (aDesiredClass.cast (aScopeValue));
      return ret;
    }
docs: Get all singleton objects registered in the respective sub-class of this
  class.
  
  @param <T>
  The singleton type to be retrieved
  @param aScope
  The scope to use. May be <code>null</code> to avoid creating a new
  scope.
  @param aDesiredClass
  The desired sub-class of this class. May not be <code>null</code>.
  @return A non-<code>null</code> list with all instances of the passed class
  in the passed scope.