{%- assign target = include.target -%}
{%- assign sep = include.sep -%}
{%- assign slice_from = target.size | minus: 1 -%}
{%- assign slice_to = target.size -%}
{%- assign last_char = target | slice: slice_from, slice_to -%}
{%- unless last_char == sep -%}
{%- assign target = target | append: sep -%}
{%- endunless -%}
{%- assign target = target | strip -%}
{{- target -}}