Help me?



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rad_sq = {"C": 3.24, "N": 1.96, "O": 2.56, "S": 3.24, "H": 1.0}
pos_volume = 0
volume_list = []
number_range = 10

for i in range(number_range):
    
    for j in range(999):
        randomX = uniform(xmin,xmax) # uses above defined min and max coordinate values to
        randomY = uniform(ymin,ymax) # generate a random point within the box
        randomZ = uniform(zmin,zmax)
        randpoint = (randomX, randomY, randomZ)

        for k in range(natom):
            a = coords[k][0] - randomX # measures distance between random point and each
            b = coords[k][1] - randomY # atom's coordinates
            c = coords[k][2] - randomZ
            dist_sq = (a*a + b*b + c*c)
            if dist_sq <= rad_sq[atomtype[i]]: # if the distance between the random point and
                pos_volume += 1                # an atomic coordinate is within van der waahls
                                               # radii, the point is inside of the protein
    box_volume = (xmax - xmin) * (ymax - ymin) * (zmax-zmin)
    box_fraction = pos_volume / 1000.          # calculates the percentage of points inside protein
    molec_vol = (box_fraction) * box_volume    # calculates protein volume based on percentage
    volume_list.append(molec_vol)

    def mean(volume_list):                  # defines mean of generated protein volume list
        length = len(volume_list)
        sum = 0
        for i in range(length):
            sum = sum + volume_list[i]
        mean_value = sum / length
        return mean_value
    mean_value = mean(volume_list)
    def stdev(volume_list, meanval = None):    # defines std dev of generated protein volume list
        if meanval == None: meanval = mean_value
        return sqrt(sum([(m - meanval)**2 for m in volume_list]) / (len(volume_list)-1))

if stdev(volume_list) < 100:   # if a reasonable std dev obtained, prints averaged volume answer
    print "Your volume is: ",mean(volume_list)
    print "Your standard deviation for this calculation is: ",stdev(volume_list)
else:                          # if std dev too high, increments the number of times through
    number_range += 10         # loop by 10 and tries again

Okay, so, see that shit in bold at the very end of this program? I'm having an issue. The program runs fine, but what I'm trying to say at the end there is that if the stdev is too high, that the entire big loop should start again at "for i in range(number_range)" (in bold up top), but increment the number_range by 10. But I can't make it loop through. Help me?!

*I realize there's probably some fancy schmancy way of figuring out the stdev shit that I don't know, but I just learned Python yesterday and what I have is fine for my purposes.