def Var(xs, mu=None, ddof=0):
 xs = np.asarray(xs)
 if (mu is None):
  mu = xs.mean()
 ds = (xs - mu)
 return (np.dot(ds, ds) / (len(xs) - ddof))

def Var ( xs , mu = None , ddof = 0 ) : xs = np . asarray ( xs ) if ( mu is None ) : mu = xs . mean ( ) ds = ( xs - mu ) return ( np . dot ( ds , ds ) / ( len ( xs ) - ddof ) )
computes variance .