from typing import Union
from typing import NoReturn


def _get_file_str(file: int) -> Union[str, NoReturn]:
	"""Convert a given integer to a file letter on a chessboard."""
	file_dict = {  # Used for int to str lookup for files
		0: 'a', 1: 'b', 2: 'c',
		3: 'd', 4: 'e', 5: 'f',
		6: 'g', 7: 'h'
	}

	return file_dict[file]