# Buggy code
def provide_context_and_uptodate(self, classification, lang, node=None):
    """Provide data for the context and the uptodate list for the list of the given classifiation.

    Must return a tuple of two dicts. The first is merged into the page's context,
    the second will be put into the uptodate list of all generated tasks.

    For hierarchical taxonomies, node is the `utils.TreeNode` element corresponding
    to the classification.

    Context must contain `title`, which should be something like 'Posts about <classification>'.
    """
    raise NotImplementedError()


# Traceback (KeyError)
########################################
TaskError - taskid:render_galleries:output/galleries/index.html
PythonAction Error
Traceback (most recent call last):
File "/home/kwpolska/virtualenvs/nikola-py2/lib/python2.7/site-packages/doit/action.py", line 360, in execute
returned_value = self.py_callable(*self.args, **kwargs)
File "/home/kwpolska/git/nikola/nikola/plugins/task/galleries.py", line 466, in render_gallery_index
self.site.render_template(template_name, output_name, context)
File "/home/kwpolska/git/nikola/scripts/../nikola/nikola.py", line 607, in render_template
template_name, None, local_context)
File "/home/kwpolska/git/nikola/nikola/plugins/template/mako.py", line 88, in render_template
data = template.render_unicode(**context)
File "/home/kwpolska/virtualenvs/nikola-py2/lib/python2.7/site-packages/mako/template.py", line 452, in render_unicode
as_unicode=True)
File "/home/kwpolska/virtualenvs/nikola-py2/lib/python2.7/site-packages/mako/runtime.py", line 807, in _render
**_kwargs_for_callable(callable_, data))
File "/home/kwpolska/virtualenvs/nikola-py2/lib/python2.7/site-packages/mako/runtime.py", line 839, in _render_context
_exec_template(inherit, lclcontext, args=args, kwargs=kwargs)
File "/home/kwpolska/virtualenvs/nikola-py2/lib/python2.7/site-packages/mako/runtime.py", line 865, in _exec_template
callable_(context, *args, **kwargs)
File "/home/kwpolska/Desktop/nikola-translated-path/cache/.mako.tmp/base.tmpl.py", line 91, in render_body
__M_writer(unicode(base.meta_translations()))
File "/home/kwpolska/Desktop/nikola-translated-path/cache/.mako.tmp/base_helper.tmpl.py", line 274, in render_meta_translations
__M_writer(unicode(_link(permalink, None, langname)))
File "/home/kwpolska/git/nikola/scripts/../nikola/nikola.py", line 765, in link
return self.path(*args, is_link=True)
File "/home/kwpolska/git/nikola/scripts/../nikola/nikola.py", line 729, in path
path = self.path_handlers[kind](name, lang)
KeyError: u'/galleries/galleries/index.html'

# Fixed code
def provide_context_and_uptodate(self, classification, lang, node=None):
    """Provide data for the context and the uptodate list for the list of the given classifiation.

    Must return a tuple of two dicts. The first is merged into the page's context,
    the second will be put into the uptodate list of all generated tasks.

    For hierarchical taxonomies, node is the `hierarchy_utils.TreeNode` element
    corresponding to the classification. Note that `node` can still be `None`
    if `also_create_classifications_from_other_languages` is `True`.

    Context must contain `title`, which should be something like 'Posts about <classification>'.
    """
    raise NotImplementedError()