The "GreedyFSA" method in Handler et al. 2016.
	Returns token position spans of valid ngrams.

def extract_finditer(pos_seq, regex=SimpleNP):
	"""The "GreedyFSA" method in Handler et al. 2016.
	Returns token position spans of valid ngrams."""
	ss = coarse_tag_str(pos_seq)

	def gen():
		for m in re.finditer(regex, ss):
			yield (m.start(), m.end())

	return list(gen())