def get_chunk_type(tok, idx_to_tag):
	"""
	Args:
		tok: id of token, ex 4
		idx_to_tag: dictionary {4: "B-PER", ...}
	Returns:
		tuple: "B", "PER"
	"""
	tag_name = idx_to_tag[tok]
	tag_class = tag_name.split('-')[0]
	tag_type = tag_name.split('-')[-1]
	return tag_class, tag_type