Develop a Python function that takes two arrays of equal size as input and returns the sum of the two arrays.
[1,2,3], [4,5,6]
def sum_arrays(arr1, arr2):
    result = []
    for i in range(len(arr1)):
        result.append(arr1[i] + arr2[i])
    return result

summed = sum_arrays([1,2,3], [4,5,6])
print(summed)