code: def determine_format(data, extension=None):
  	
  
  	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
docs: 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).