First line in relatorio

how can i distinguish the first line

<for each="line in invoice.invoice_address.full_address.split('\n')">
<line>
</for>

something like

<choose>
<when line[0]>
<line>
</when>
<otherwise>
<line>
</otherwise>
</choose>
<for each="i, line in enumerate(invoice.invoice_address.full_address.split('\n'))">
<if test="i==0">
FIRST LINE
</if>
</for>