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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 highlightSubsequence(sequence, x1, x2, start=' [', stop = '] ') : 	"""returns a sequence where the subsequence in [x1, x2[ is placed 	in bewteen 'start' and 'stop'"""


	seq = list(sequence)
	print x1, x2-1, len(seq)
	seq[x1] = start + seq[x1]
	seq[x2-1] = seq[x2-1] + stop
	return ''.join(seq)