docs: @Override
  	public boolean eIsSet(int featureID)
  	{
  		switch (featureID)
  		{
  			case SarlPackage.SARL_SKILL__EXTENDS:
  				return extends_ != null;
  			case SarlPackage.SARL_SKILL__IMPLEMENTS:
  				return implements_ != null && !implements_.isEmpty();
  		}
  		return super.eIsSet(featureID);
  	}