def merge_sort(arr):
	if len(arr) <= 1:
		return arr
	mid = len(arr) // 2
	left = merge_sort(arr[ :mid])
	right = merge_sort(arr[mid: ])
	return merge(left, right)

def merge(left, right):
	result = []
	i=j= 0
	while i < len(left) and j < len(right):
		if left[i] <= right[j]:
			result. append(left[i])
			i += 1
		else:
			result .append(right[j])
			j += 1
	result .extend(left[i:])
	result.extend(right[j:])
	return result

data = [64, 34, 25, 12, 22, 11, 90]
print("Merge Sort:", merge_sort(data.copy()))

## Merge Sort: [11, 12, 22, 25, 34, 64, 90]