新手求助 PyScripter调试问题

[Will]

代码：
class Person:
'''Represents a person.'''
population=0

def __init__(self,name):
'''Initializes the person's data.'''
self.name=name
print '(Initializing %s)' %self.name

#When this person is created, he/she adds to the
population
Person.population+=1

def __del__(self):
'''I am dying.'''
print '%s says bye.' %self.name

Person.population-=1

if Person.population==0:
print 'I am the last one.'
else:
print 'There are still %d people left.'
%Person.population

def sayHi(self):
'''Greeting by the person.

Really, that's all it does.'''
print 'Hi, my name is %s.' %self.name

def howMany(self):
'''Prints the current population.'''
if Person.population==1:
print 'I am the only person here.'
else:
print 'We have %d persons here.'
%Person.population

swaroop=Person('Swaroop')
swaroop.sayHi()
swaroop.howMany()

kalam=Person('Abdul Kalam')
kalam.sayHi()
kalam.howMany()

swaroop.sayHi()
swaroop.howMany()


这是简明Python教程里的一个例子
我使用PyScripter调试的

2个问题
1.为什么我run第一次和第二次的结果是不同的
2.如何设置断点调试python程序