关于Python3.6下登陆接口的尝试

编者按：
README:此代码为用户登陆界面，添加了寻求帮助选项。
1.学习了基本数据类型，string, int，以及while循环，continue, break, if, elif, else条件语句，“x".format（x）变量替代
2.上网搜的dictionary用法，由于用的是python3.6，老教程不太管用，尝试了2天方才悟出正确的增加键值用法，希望技术大牛留言给予更多启发！

 1 dict_profile = {"Alex":"alex1234", "Bob":"bob123", "Cathy":"cathy1234",
 2                 "David":"david12345", "Eva":"eva123"}
 3 #Save the rightful username and password in the dictionary
 4 black_list = { } #Create a list for not exist username
 5 email = "send an email to our help desk for further solutions"
 6 chance = 6 #After 3 valid trys the system will be locked
 7 username = input("username:")
 8 password = input("password:")
 9 #password = getpass.getpass("password:")
10 while chance > 0:
11     if username not in dict_profile.keys(): #Search for username in the profile
12       black_list["{}".format(username)]="{}".format(password)
13       username = input("The username does not exist, please try again:")
14       chance = chance - 1
15       if username in black_list.keys(): #Run a security check
16         username = input("The username does not exist and has been locked, please try other combinations:")
17         chance = chance - 2 # Deduct 2 chances to punish whoever abuses the system
18     elif password != dict_profile.get(username,""): #Find the value of password to match with the username
19       print("The password does not match the username, do you have problem with memorizing things?")
20       customized_option = input("Y/N")
21       if customized_option != "N":
22         print("Please ask your partner or {}.".format(email))
23         break
24       else:
25         password = input("Please enter your password with caution:")
26         chance = chance - 1
27     else:
28         print("Welcome my lord {_name}! Please wait while login...".format(_name = username))
29         break
30 if chance <= 0:
31     print("The system is locked since you have too many incorrect entries!Please {}.".format(email))