def max_subarray(numbers):
    """Find the largest sum of any contiguous subarray."""
    best_sum = float('-inf')
    current_sum = 0
    for x in numbers:
        current_sum = max(x, current_sum + x)
        best_sum = max(best_sum, current_sum)
    return best_sum

print(max_subarray([100, -5, 500]))