sort two sorted array, return one sorted array

sort.py

def sort(a, b):
	a_index=0
	b_index=0
	result = []
	while a_index < len(a) or b_index < len(b):
		if b_index >= len(b):
			result.append(a[a_index])
			a_index+=1
		elif a_index >= len(a):
			result.append(b[b_index])
			b_index+=1
		elif a[a_index] < b[b_index]:
			result.append(a[a_index])
			a_index+=1
		else:
			result.append(b[b_index])
			b_index+=1
	return result