SpEL check elements in 2D array

Hi how to check using SpEL that all ProductType.type is driver

   <r:Certificates>
    <r:Product>
        <r:ProductType type="driver">...</r:ProductType>
    </r:Product>
    <r:Product>
        <r:Purpose>...</r:Purpose>
        <r:Purpose>...</r:Purpose>
        <r:CompetentAuthority>...</r:CompetentAuthority>
        <r:ProductType type="driver">...</r:ProductType>
        <r:ProductType type="targetType">...</r:ProductType>
    </r:Product>
</r:Certificates>