How to sort nested nodes xml

I have below menioned xml.

    <?xml version="1.0" encoding="UTF-8"?>
<insiders>
   <insider>
      <linkages>
         <linkage>
            <owner id="112025">
               <namestrings>
                  <namestring />
               </namestrings>
            </owner>
            <relationshipHistory>
               <relationship code="201" />
            </relationshipHistory>
         </linkage>
      </linkages>
   </insider>
   <insider>
      <linkages>
         <linkage>
            <owner id="100354">
               <namestrings>
                  <namestring>KAITUE RAIMO KUOLINPESÄ</namestring>
               </namestrings>
            </owner>
            <relationshipHistory>
               <relationship code="302">
                  <from>1998-10-23</from>
               </relationship>
            </relationshipHistory>
         </linkage>
         <linkage>
            <owner id="126799">
               <namestrings>
                  <namestring />
               </namestrings>
            </owner>
            <relationshipHistory>
               <relationship code="204">
                  <from>2014-09-09</from>
               </relationship>
               <relationship code="201">
                  <to>2014-09-08</to>
               </relationship>
            </relationshipHistory>
         </linkage>
      </linkages>
   </insider>
</insiders>

I want to sort the relationshipHistory node based on code attribute, In mentioned xml code=201 element should first then code=204 after it. can any one please help me how can I do it?