def grab_to_file(filename, childprocess=None, backend=None):
if childprocess is None:<EOL><INDENT>childprocess = childprocess_default_value()<EOL><DEDENT>return _grab(to_file=True, childprocess=childprocess,<EOL>backend=backend, filename=filename)<EOL>
Copy the contents of the screen to a file. Internal function! Use
    PIL.Image.save() for saving image to file.

    :param filename: file for saving
    :param childprocess: see :py:func:`grab`
    :param backend: see :py:func:`grab`