request_data = {
 'data': {
 'type': 'comments',
 'id': self.second_comment.id,
 'attributes': {
 'meta': "test"
 }
 }
 }

Traceback (most recent call last):
 File "/home/christian/.pyenv/versions/3.6.7/envs/drf-json-api/lib/python3.6/site-packages/django/core/handlers/exception.py", line 34, in inner
 response = get_response(request)
 File "/home/christian/.pyenv/versions/3.6.7/envs/drf-json-api/lib/python3.6/site-packages/django/core/handlers/base.py", line 145, in _get_response
 response = self.process_exception_by_middleware(e, request)
 File "/home/christian/.pyenv/versions/3.6.7/envs/drf-json-api/lib/python3.6/site-packages/django/core/handlers/base.py", line 143, in _get_response
 response = response.render()
 File "/home/christian/.pyenv/versions/3.6.7/envs/drf-json-api/lib/python3.6/site-packages/django/template/response.py", line 106, in render
 self.content = self.rendered_content
 File "/home/christian/.pyenv/versions/3.6.7/envs/drf-json-api/lib/python3.6/site-packages/rest_framework/response.py", line 72, in rendered_content
 ret = renderer.render(self.data, accepted_media_type, context)
 File "/home/christian/dev/django-rest-framework-json-api/rest_framework_json_api/renderers.py", line 572, in render
 json_api_meta.update(self.extract_root_meta(serializer, serializer_data))
AttributeError: 'str' object has no attribute 'update'