def issorted(comparables, lo=0, hi=None):
	"""Return True if comparables is sorted in ascending order

	Arguments:
	comparables -- an array of which the elements can be compared
	lo          -- lower bound of indices (default 0)
	hi          -- higher bound of indices (default None)
	"""
	if hi is None:
		hi = len(comparables)

	for i in range(lo, hi-1):
		if comparables[i] > comparables[i+1]:
			return False
	return True