docs: def _grid_in_property(field_name, docstring, read_only=False,
                        closed_only=False):
      """Create a GridIn property."""
      def getter(self):
          if closed_only and not self._closed:
              raise AttributeError("can only get %r on a closed file" %
                                   field_name)
          # Protect against PHP-237
          if field_name == 'length':
              return self._file.get(field_name, 0)
          return self._file.get(field_name, None)
  
      def setter(self, value):
          if self._closed:
              self._coll.files.update_one({"_id": self._file["_id"]},
                                          {"$set": {field_name: value}})
          self._file[field_name] = value
  
      if read_only:
          docstring += "\n\nThis attribute is read-only."
      elif closed_only:
          docstring = "%s\n\n%s" % (docstring, "This attribute is read-only and "
                                    "can only be read after :meth:`close` "
                                    "has been called.")
  
      if not read_only and not closed_only:
          return property(getter, setter, doc=docstring)
      return property(getter, doc=docstring)