Determine the format of an audio file.

	Parameters:
		data (bytes-like object, str, os.PathLike, or file-like object):
			A bytes-like object, filepath, path-like object
			or file-like object of an audio file.
		extension (str): The file extension of the file.
			Used as a tie-breaker for formats that can
			be used in multiple containers (e.g. ID3).

def determine_format(data, extension=None):
	"""Determine the format of an audio file.

	Parameters:
		data (bytes-like object, str, os.PathLike, or file-like object):
			A bytes-like object, filepath, path-like object
			or file-like object of an audio file.
		extension (str): The file extension of the file.
			Used as a tie-breaker for formats that can
			be used in multiple containers (e.g. ID3).
	"""

	if isinstance(data, (os.PathLike, str)):
		data = open(data, 'rb')

	data_reader = DataReader(data)
	data_reader.seek(0, os.SEEK_SET)
	d = data_reader.read(4)

	if d.startswith((b'ID3', b'\xFF\xFB')):  # TODO: Catch all MP3 possibilities.
		if extension is None or extension.endswith('.mp3'):
			return MP3

	if d.startswith((b'fLaC', b'ID3')):
		if extension is None or extension.endswith('.flac'):
			return FLAC

	if d.startswith(b'RIFF'):
		if extension is None or extension.endswith('.wav'):
			return WAV

	return None