How to allow an empty string with check condition in xml transformation?

Hi, experts.

U have this condition at mine xml transformation

<tt:cond s-check=”not-initial(ref(‘ROOT.PROVIDER.BRANCHCODE’))”>
<branchCode tt:value-ref=”ROOT.PROVIDER.BRANCHCODE”/>
</tt:cond>

and call the transformation

call transformation (LV_TRANS_NAME)
source xml XML_FINAL2
result ROOT = IT_TAB.

If document has empty <branchCode></branchCode> – everything is ok, but some documents have

space inside ( <branchCode></branchCode> )and i’m getting dump.

How to allow an space and save check to not initial.
Type of BRANCHCODE – CHAR4.