(obj, param_list, normalize)
return tuple(ret_vector)
Evaluates the surface tangent vectors at the given list of parameter values.

    :param obj: input surface
    :type obj: abstract.Surface
    :param param_list: parameter list
    :type param_list: list or tuple
    :param normalize: if True, the returned vector is converted to a unit vector
    :type normalize: bool
    :return: a list containing "point" and "vector" pairs
    :rtype: tuple
Evaluates the surface tangent vectors at the given list of parameter values.
Evaluates the surface tangent vectors at the given list of parameter values .
def tangent_surface_single_list(obj, param_list, normalize):
    """ Evaluates the surface tangent vectors at the given list of parameter values.

    :param obj: input surface
    :type obj: abstract.Surface
    :param param_list: parameter list
    :type param_list: list or tuple
    :param normalize: if True, the returned vector is converted to a unit vector
    :type normalize: bool
    :return: a list containing "point" and "vector" pairs
    :rtype: tuple
    """
    ret_vector = []
    for param in param_list:
        temp = tangent_surface_single(obj, param, normalize)
        ret_vector.append(temp)
    return tuple(ret_vector)
def tangent_surface_single_list ( obj , param_list , normalize ) : ret_vector = [ ] for param in param_list : temp = tangent_surface_single ( obj , param , normalize ) ret_vector . append ( temp ) return tuple ( ret_vector )