def get_by_username(self, username):
        """Retrieve user by username"""
        res = filter(lambda x: x.username == username, self.users.values())
        if len(res) > 0:
            return res[0]
        return None
def get_by_username(self, username):
        
        res = filter(lambda x: x.username == username, self.users.values())
        if len(res) > 0:
            return res[0]
        return None
def get_by_username ( self , username ) : res = filter ( lambda x : x . username == username , self . users . values ( ) ) if len ( res ) > 0 : return res [ 0 ] return None
Retrieve user by username
Retrieve user by username