def bessel(N, Wn, btype='low', analog=False, output='ba', norm='phase'):
 return iirfilter(N, Wn, btype=btype, analog=analog, output=output, ftype=('bessel_' + norm))

def bessel ( N , Wn , btype = 'low' , analog = False , output = 'ba' , norm = 'phase' ) : return iirfilter ( N , Wn , btype = btype , analog = analog , output = output , ftype = ( 'bessel_' + norm ) )
bessel/thomson digital and analog filter design .