def update_quantity(user = nil, reason = nil, comment = nil, effective_from_date = nil, force_new_quantity_with_past_effective_date = nil, options = {})
        params                  = {}
        params[:effectiveFromDate] = effective_from_date unless effective_from_date.nil?
        params[:forceNewQuantityWithPastEffectiveDate] = force_new_quantity_with_past_effective_date unless force_new_quantity_with_past_effective_date.nil?