Lists of random walks.

def randompaths(request, num_paths=1, size=250, mu=0, sigma=1):
    '''Lists of random walks.'''
    r = []
    for p in range(num_paths):
        v = 0
        path = [v]
        r.append(path)
        for t in range(size):
            v += normalvariate(mu, sigma)
            path.append(v)
    return r