def spherical_kn(n, z, derivative=False):
 if derivative:
  return _spherical_kn_d(n, z)
 else:
  return _spherical_kn(n, z)

def spherical_kn ( n , z , derivative = False ) : if derivative : return _spherical_kn_d ( n , z ) else : return _spherical_kn ( n , z )
modified spherical bessel function of the second kind or its derivative .