cpython/Lib/test/xmltestdata/c14n-20/out_inC14N2_c14nDefault.xml

<doc>
   <clean>   </clean>
   <dirty>   A   B   </dirty>
   <mixed>
      A
      <clean>   </clean>
      B
      <dirty>   A   B   </dirty>
      C
   </mixed>
</doc>