docs: def get_source(self, environment, template):
          """.. seealso:: :meth:`jinja2.loaders.FileSystemLoader.get_source`
          """
          pieces = jinja2.loaders.split_template_path(template)
          for searchpath in self.searchpath:
              filename = os.path.join(searchpath, *pieces)
              if self.enable_glob:
                  files = sorted(glob.glob(filename))
              else:
                  files = [filename]
              contents_mtimes = list(_load_file_itr(files, self.encoding))
              if not contents_mtimes:
                  continue
  
              contents = ''.join(cm[0] for cm in contents_mtimes)
              mtimes = [cm[1] for cm in contents_mtimes]
  
              def uptodate():
                  """function to check of these are up-to-date.
                  """
                  try:
                      return all(os.path.getmtime(fn) == mt for fn, mt
                                 in zip(files, mtimes))
                  except OSError:
                      return False
  
              return contents, filename, uptodate
  
          raise jinja2.exceptions.TemplateNotFound(template)