This option is used to specify the columns that will be used as filters to find the learner.
Note: If several learner accounts match the chosen traineeSearchField, the oldest account will be updated.
Inside a traineeSearchField tag, it is possible to set multiple fields at the same time, in which case the learners will be searched by all these columns jointly:
<options>
<traineeSearchField>
<candidateRefNumber/>
<candidateEmail/>
<candidateLogin/>
<custom>SOME_GUID</custom>
</traineeSearchField>
</options>