class_docstr: FileSystemLoader subclass that is not so strict about '..'  entries in
  template names.
class_docstr_tok: ["FileSystemLoader","subclass","that","is","not","so","strict","about","'","..","'","entries","in","template","names","."]
code: def get_source(
      self, environment: Environment, template: str
  ) -> tuple[str, str, Callable]:
      for searchpath in self.searchpath:
          filename = path.join(searchpath, template)
          f = open_if_exists(filename)
          if f is not None:
              break
      else:
          raise TemplateNotFound(template)
  
      with f:
          contents = f.read().decode(self.encoding)
  
      mtime = path.getmtime(filename)
  
      def uptodate() -> bool:
          try:
              return path.getmtime(filename) == mtime
          except OSError:
              return False
  
      return contents, filename, uptodate
  
imports: from __future__ import annotations
  from os import path
  from pprint import pformat
  from typing import TYPE_CHECKING, Any, Callable
  from jinja2 import BaseLoader, FileSystemLoader, TemplateNotFound
  from jinja2.sandbox import SandboxedEnvironment
  from jinja2.utils import open_if_exists
  from sphinx.application import TemplateBridge
  from sphinx.util import logging
  from sphinx.util.osutil import mtimes_of_files
label_desc: Use image node_id 1 for calling the SphinxFileSystemLoader obj's underlying member method code with example usage: obj.get_source(environment, template) and returns: contents,  filename,  uptodate, unknown, False