{% for song in songs %}
{% if not song.artist[0] is in ['A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'] %}
{% elif song.artist[0]|upper != ns.start_letter|upper %}
{% set ns.start_letter=song.artist[0] %}