Example Error: argument of type 'bool' is not iterable

[JavierRuano]

I have tried with the example https://django-nvd3.readthedocs.io/en/latest/classes-doc/line-with-focus-chart.html

But i have the error: argument of type 'bool' is not iterable

backtrace: Traceback (most recent call last): File "/home/javiero/.local/lib/python3.7/site-packages/django/core/handlers/exception.py", line 34, in inner response = get_response(request) File "/home/javiero/.local/lib/python3.7/site-packages/django/core/handlers/base.py", line 115, in _get_response response = self.process_exception_by_middleware(e, request) File "/home/javiero/.local/lib/python3.7/site-packages/django/core/handlers/base.py", line 113, in _get_response response = wrapped_callback(request, *callback_args, *callback_kwargs) File "/home/javiero/webSite/stream/polls/views.py", line 245, in MapProgres return render_to_response('polls/linewithfocuschart.html', data) File "/home/javiero/.local/lib/python3.7/site-packages/django/shortcuts.py", line 27, in render_to_response content = loader.render_to_string(template_name, context, using=using) File "/home/javiero/.local/lib/python3.7/site-packages/django/template/loader.py", line 62, in render_to_string return template.render(context, request) File "/home/javiero/.local/lib/python3.7/site-packages/django/template/backends/django.py", line 61, in render return self.template.render(context) File "/home/javiero/.local/lib/python3.7/site-packages/django/template/base.py", line 171, in render return self._render(context) File "/home/javiero/.local/lib/python3.7/site-packages/django/template/base.py", line 163, in _render return self.nodelist.render(context) File "/home/javiero/.local/lib/python3.7/site-packages/django/template/base.py", line 937, in render bit = node.render_annotated(context) File "/home/javiero/.local/lib/python3.7/site-packages/django/template/base.py", line 904, in render_annotated return self.render(context) File "/home/javiero/.local/lib/python3.7/site-packages/django/template/library.py", line 192, in render output = self.func(resolved_args, **resolved_kwargs) File "/usr/local/lib/python3.7/dist-packages/django_nvd3/templatetags/nvd3_tags.py", line 39, in load_chart if 'x_is_date' not in kw_extra: TypeError: argument of type 'bool' is not iterable