クラスの属性の値を変更することが可能です．例えば，description 属性と priority 属性を変更して表示してみます．
class Issue:
def __init__(self, subject):
self.subject = subject
self.description = ''
self.priority = 0
self.closed = False
issue1 = Issue('件名です')
print('subject :', issue1.subject)
print('description :', issue1.description)
print('priority :',issue1.priority)
print('closed :', issue1.closed)
print('--------------------------')
issue1.description = '問題の詳細を設定します'
issue1.priority = 1
print('subject :', issue1.subject)
print('description :', issue1.description)
print('priority :',issue1.priority)
print('closed :', issue1.closed)
subject : 件名です description : priority : 0 closed : False -------------------------- subject : 件名です description : 問題の詳細を設定します priority : 1 closed : False