Golden Ration method to calculate Fibonacci Numbers

fibonacci.py

def fibonacci_goldenratio(target):
    """
    This method works by calculating the golden ratio, and then
    raising the golden ration to the power of n, whereby n is the position of the fibonacci sequence.

    As we look for higher and higher values of n, rounding errors throw us off. This method works for values of n
    less than 72 or so.

    :param target:
    :return:

    >>> fibonacci_goldenratio(80)
    23416728348467685

    """
    import math

    if target < 2:
        return target

    if target > 71:
        return matrix_fibonacci(target)

    sqrt5 = math.sqrt(5)
    golden_ratio = (1 + sqrt5) / 2

    return math.floor(math.pow(golden_ratio, target) / sqrt5)