Problems with creating my own instance

I am currently trying to create my own Lemmy instance and am following the join-lemmy.org docker guide. But unfortunately docker compose up doesn't work with the default config and throw's a yaml: line 32: found character that cannot start any token error. Is there something I can do to fix this?

The section in question is

 % if lemmy_env_vars is defined and lemmy_env_vars|length > 0 %}

    
{% for item in lemmy_env_vars %}
{% for key, value in item.items() %}
      - {{ key }}={{ value }}
{% endfor %}
{% endfor %}
{% endif %}