working merge sort

merge.py

def merge(array1, array2):
    a_index = 0
    b_index = 0    
    result = []
    while a_index < len(array1) or b_index < len(array2):
        if a_index >= len(array1) or array1[a_index] > array2[b_index]:
            result.append(array2[b_index])
            b_index+=1
        elif b_index >= len(array2) or array1[a_index] <= array2[b_index]:
            result.append(array1[a_index])
            a_index+=1
            
    return result
        
        
a = [1, 2, 5]
b = [3, 4, 6]
print(merge(a, b))