Using dict like C switch - python-2.7

Question

class checkevent:
def __init__(self,fromuser):
self.fromuser = fromuser
def openid_check(self):# use sqlalchemy
exist_user = User.query.filter_by(openid = self.fromuser).first()
if exist_user is None:
text = u'请绑定后在使用'
return text
def grade(self):
openid_check()
exist_user = User.query.filter_by(openid = self.fromuser).first()
geturp = urp(exist_user.username, exist_user.password_urp) #the function
return geturp #return the grades as text
def key_check(self,x): # use dict like switch
{'grade': self.grade
}
contents = checkevent('ozvT4jlLObJWzz2JQ9EFsWSkdM9U').key_check('grade')
print contents
It's always return None,I want to get a value
and it's the right way to use dict?

Answer 1

There's no return statement in key_check, so naturally it doesn't return anything. You're basically missing the last bit of the implementation: once you look up the appropriate function by name, you need to call that function and return the result.
def key_check(self, key): # "x" is a meaningless name; use something meaningful
lookup = {
'grade': self.grade
}
func = lookup[key] # Look up the correct method
return func() # Call that method and return its result
Technically you could in-line all that into one statement if you really wanted to, but unless performance is at a premium I wouldn't recommend it as the readability suffers.