docs: def get_extended_summaryf(self, *args, **kwargs):
          """Extract the extended summary from a function docstring
  
          This function can be used as a decorator to extract the extended
          summary of a function docstring (similar to :meth:`get_sectionsf`).
  
          Parameters
          ----------
          ``*args`` and ``**kwargs``
              See the :meth:`get_extended_summary` method. Note, that the first
              argument will be the docstring of the specified function
  
          Returns
          -------
          function
              Wrapper that takes a function as input and registers its summary
              via the :meth:`get_extended_summary` method"""
          def func(f):
              doc = f.__doc__
              self.get_extended_summary(doc or '', *args, **kwargs)
              return f
          return func