docs: def find_one(self, filter=None, *args, **kwargs):
          """Get a single file from gridfs.
  
          All arguments to :meth:`find` are also valid arguments for
          :meth:`find_one`, although any `limit` argument will be
          ignored. Returns a single :class:`~gridfs.grid_file.GridOut`,
          or ``None`` if no matching file is found. For example::
  
              file = fs.find_one({"filename": "lisa.txt"})
  
          :Parameters:
            - `filter` (optional): a dictionary specifying
              the query to be performing OR any other type to be used as
              the value for a query for ``"_id"`` in the file collection.
            - `*args` (optional): any additional positional arguments are
              the same as the arguments to :meth:`find`.
            - `**kwargs` (optional): any additional keyword arguments
              are the same as the arguments to :meth:`find`.
          """
          if filter is not None and not isinstance(filter, Mapping):
              filter = {"_id": filter}
  
          for f in self.find(filter, *args, **kwargs):
              return f
  
          return None