Werkzeug Internal Server Error

traceback.txt

Traceback (most recent call last):
  File "/home/vagrant/env/lib/python2.7/site-packages/django/contrib/staticfiles/handlers.py", line 64, in __call__
    return self.application(environ, start_response)
  File "/home/vagrant/env/lib/python2.7/site-packages/django/core/handlers/wsgi.py", line 187, in __call__
    response = self.get_response(request)
  File "/home/vagrant/env/lib/python2.7/site-packages/django/core/handlers/base.py", line 199, in get_response
    response = self.handle_uncaught_exception(request, resolver, sys.exc_info())
  File "/home/vagrant/env/lib/python2.7/site-packages/django/core/handlers/base.py", line 236, in handle_uncaught_exception
    return debug.technical_500_response(request, *exc_info)
  File "/home/vagrant/env/lib/python2.7/site-packages/django_extensions/management/technical_response.py", line 5, in null_technical_500_response
    six.reraise(exc_type, exc_value, tb)
  File "/home/vagrant/env/lib/python2.7/site-packages/django/core/handlers/base.py", line 137, in get_response
    response = response.render()
  File "/home/vagrant/env/lib/python2.7/site-packages/django/template/response.py", line 103, in render
    self.content = self.rendered_content
  File "/home/vagrant/env/lib/python2.7/site-packages/rest_framework/response.py", line 59, in rendered_content
    ret = renderer.render(self.data, media_type, context)
  File "/home/vagrant/env/lib/python2.7/site-packages/rest_framework/renderers.py", line 736, in render
    context = self.get_context(data, accepted_media_type, renderer_context)
  File "/home/vagrant/env/lib/python2.7/site-packages/rest_framework/renderers.py", line 686, in get_context
    raw_data_post_form = self.get_raw_data_form(data, view, 'POST', request)
  File "/home/vagrant/env/lib/python2.7/site-packages/rest_framework/renderers.py", line 636, in get_raw_data_form
    content = renderer.render(serializer.data, accepted, context)
  File "/home/vagrant/env/lib/python2.7/site-packages/rest_framework/serializers.py", line 463, in data
    ret = super(Serializer, self).data
  File "/home/vagrant/env/lib/python2.7/site-packages/rest_framework/serializers.py", line 208, in data
    raise AssertionError(msg)
AssertionError: When a serializer is passed a `data` keyword argument you must call `.is_valid()` before attempting to access the serialized `.data` representation.
You should either call `.is_valid()` first, or access `.initial_data` instead.