def standard_deviation(numbers):
    """Return standard deviation."""
    numbers = list(numbers)
    if not numbers:
        return 0
    mean = sum(numbers) / len(numbers)
    return (sum((n - mean) ** 2 for n in numbers) /
            len(numbers)) ** .5
def standard_deviation ( numbers ) : numbers = list ( numbers ) if not numbers : return 0 mean = sum ( numbers ) / len ( numbers ) return ( sum ( ( n - mean ) ** 2 for n in numbers ) / len ( numbers ) ) ** .5
Return standard deviation.