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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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())