docs: def _call_special_functions(self, filetype, template, **kwargs):
          ''' Call the special functions found in a template path
  
          Calls special functions indicated by %methodname found in the
          sdss_paths.ini template file, and replaces the %location in the path
          with the returned content.
  
          Parameters:
              filetype (str):
                  template name of file
              template (str):
                  the template path
              kwargs (dict):
                  Any kwargs needed to pass into the methods
  
          Returns:
              The expanded template path 
          '''
          # Now call special functions as appropriate
          functions = re.findall(r"\%\w+", template)
          if not functions:
              return template
  
          for function in functions:
              try:
                  method = getattr(self, function[1:])
              except AttributeError:
                  return None
              else:
                  value = method(filetype, **kwargs)
                  template = re.sub(function, value, template)
          return template