{{ bos_token }}{%- if messages[0]['role'] == 'system' -%}  {%- set first_user_prefix = messages[0]['content'] + '\n\n' -%}  {%- set loop_messages = messages[1:] -%}{%- else -%}  {%- set first_user_prefix = '' -%}  {%- set loop_messages = messages -%}{%- endif -%}{%- for message in loop_messages -%}  {%- if (message['role'] == 'user') != (loop.index0 % 2 == 0) -%}    {{ raise_exception('Conversation roles must alternate user/assistant/user/assistant/...') }}  {%- endif -%}  {%- if message['role'] == 'assistant' -%}    {{ '<start_of_turn>model\n' }}    {% generation %}{{ message['content'] | trim }}{{ '<end_of_turn>\n' }}    {% endgeneration %}  {%- else -%}    {{ '<start_of_turn>' + message['role'] + '\n' + (first_user_prefix if loop.first else '') + (message['content'] | trim) + '<end_of_turn>\n' }}  {%- endif -%}{%- endfor -%}{%- if add_generation_prompt -%}  {{ '<start_of_turn>model\n' }}{%- endif -%}