class Pen(object):
def __init__(self, mean_radius = None, length = None):
self.usage = "Is used to apply ink trails to drawing surfaces"
self.mean_radius = mean_radius
self.length = length
class FountainPen(Pen):
def __init__(self, manufacturer = "Waterman", *args, **kwargs):
Pen.__init__(self, *args, **kwargs)
self.manufacturer = manufacturer
self.cartridge_state = "non-empty"
>>> instance_FP = FountainPen(5, 1)
>>> instance_FP.mean_radius
>>> print instance_FP.mean_radius
1
>>> print instance_FP.length
None
5
在 的实例化中作为参数传递的整数会发生什么FountainPen
?为什么print instance_FP.mean_radius
返回1
而不返回5
?