'Create a new file in GridFS.
Returns a new :class:`~gridfs.grid_file.GridIn` instance to
which data can be written. Any keyword arguments will be
passed through to :meth:`~gridfs.grid_file.GridIn`.
If the ``"_id"`` of the file is manually specified, it must
not already exist in GridFS. Otherwise
:class:`~gridfs.errors.FileExists` is raised.
:Parameters:
- `**kwargs` (optional): keyword arguments for file creation'

def new_file(self, **kwargs):

    return GridIn(self.__collection, **kwargs)
