code: def register_entry(self, navbar_kwargs):
          
          # Add a new rule for each level in the path.
          path = navbar_kwargs.pop('path')
          # If a single object is used rather than an iterable (including
          # a single string), wrap it before using.
          if not hasattr(path, '__iter__') or isinstance(path, basestring):
              path = [path]
  
          entry_group = self.navbar_entries
          # HACK: I'd like to intelligently replace the URL rule in the
          # case where the intended rule is provided, but the function has
          # already created a blank "placeholder" rule for it. There are
          # probably nicer ways to approach this, but it works.
          for name, is_last in iter_islast(path):
              kwargs = deepcopy(navbar_kwargs)
              kwargs['name'] = name
              for existing_entry in entry_group:
                  # If there's an existing entry for this "link", use it
                  # instead of creating a new one. If this existing entry
                  # has no rule and this is the last item in ``path``, the
                  # rule was intended to be assigned to this entry, so
                  # overwrite the blank rule with the one provided via
                  # ``navbar_kwargs``.
                  if existing_entry.name == name:
                      entry = existing_entry
                      if is_last:
                          entry.endpoint = kwargs['endpoint']
                      break
              else:
                  # If we can't find an existing entry, create one with a
                  # blank endpoint. If this rule is not the final one in
                  # the list, the endpoint was not intended for this, so
                  # don't assign it.
                  if not is_last:
                      kwargs['endpoint'] = None
                  entry = NavbarEntry(**kwargs)
                  entry_group.add(entry)
              entry_group = entry.children
docs: Register a navbar entry with the copilot.
  
          Args:
              navbar_kwargs (dict): Arguments passed to the
                  :class:`NavbarEntry` instance.