def levenshtein_distance(a, b) :
	""" return the levenshtein distance between two strings of list of """

	len_a = len(a)
	len_b = len(b)
	
	d = square_list(len_a+1, len_b+1)
	
	for i in range(1, len_a+1) :
		d[i][0] = i
	for j in range(1, len_b+1) :
		d[0][j] = j
		
	for j in range(1, len_b+1) :
		for i in range(1, len_a+1) :
			if a[i-1] == b[j-1] :
				d[i][j] = d[i-1][j-1]
			else :
				d[i][j] = min(d[i-1][j], d[i][j-1], d[i-1][j-1]) + 1
	return d[-1][-1]
 return the levenshtein distance between two strings of list of 
recipes/Python/578810_Levenshtein_my_love/recipe-578810.py