{{- bos_token }}
{%- set system_message = '' %}
{%- if messages[0]['role'] == 'system' %}
    {%- set system_message = messages[0]['content'] %}
    {%- set messages = messages[1:] %}
{%- endif %}
{%- for message in messages %}
    {%- if (message['role'] != 'user') and (message['role'] != 'assistant') %}
        {{- raise_exception('Only user and assistant roles are supported after the initial optional system message.') }}
    {%- endif %}
    {%- if (message['role'] == 'user') != (loop.index0 % 2 == 0) %}
        {{- raise_exception('After the optional system message, conversation roles must alternate user/assistant/user/assistant/...') }}
    {%- endif %}
    {%- set content = message['content'] %}
    {%- if loop.index0 == 0 and system_message %}
        {%- set content = system_message + '\n\n' + message['content'] %}
    {%- endif %}
    {{- '<|im_start|>' + message['role'] + '\n' + content + '<|im_end|>' + '\n' }}
{%- endfor %}
{%- if add_generation_prompt %}
    {{- '<|im_start|>assistant\n' }}
{%- endif %}