def METHOD_NAME(tag):
	""" Convert between a Penn Treebank tag to a simplified Wordnet tag """
	if tag.startswith('N'):
		return 'n'
	if tag.startswith('V'):
		return 'v'
	if tag.startswith('J'):
		return 'a'
	if tag.startswith('R'):
		return 'r'
	return None