#!/usr/bin/env python

import math
import numpy as np

def sd1(rr):
	sdnn = np.std(rr)
	return math.sqrt(0.5 * sdnn * sdnn)
[(7, 'numpy.std', 'np.std', True, 'import numpy as np\n'), (8, 'math.sqrt', 'math.sqrt', False, 'import math\n')]