Question

How do I make my code print out the text in the ServiceNotifier class?

Python Code:

class ServiceNotifier:
#Subject responsible for notifying registered observer objects

   Observer = [Email, SMS, Phone]
  
   def attach(self):
   #add new observer
       Observer.append(insertnewobserverhere)

   def dettach(self):
   #remove an observer
       Observer.pop(insertnewobserverhere)

   def servicenotifier(self):
       for observers in Observer:
           print("Due to the forecast for tomorrow, all university and campus operations will be closed.")
      

##########################################################

def Service():
#Main code to execute
   for alerts in ServiceNotifier():
       notify = alerts.servicenotifier()
       return notify

if __name__ == "__main__":
#Exectues the weather alert system
   Service()

Answer 1

The problem with your code is, Class and its attributes have not been defined correctly.

Problems are with the syntax and not using some keywords. This has been Explained below.

Note that answer is provided only for the question asked which is on How to make the code to print the message.

Only The errors and Problems are covered with some suggestions .

1) Every class may have Constructor. Constructor is a function which create an object of the class and return the object.

Any parameters to set the values to the class variables can be written in init().

It can be defined as

Although constructors may not be used , but it is a good habit to use the constructors.

*The keyword 'self' has been explained in later parts below.

2) Also class objects/ instances are not iterable.

Your code gives the following error.

You must first create an object and then use the attribute or call the method in the class/ Instance.

Hence , change the code of Service function. Objects are created first as follows and functions are called.

3) And in the methods of class, you have a parameter self. The keyword 'self' refers to the object itself.

Hence if you run your code using just 'Observer' it raises an error saying ' Observer is not defined'.

Hence you must use 'self.Observer' which refers to the Observer attribute in the instance of class.Therefore edit the following method, and all other functions using 'self' keyword

if Observer = [ [Ob1] , [Ob2] ,[Ob2] ] , The code prints the above message three(3) times.

Suggestions and Additional Corrections or improvements.

* You might use( if it requires according to the question), is you should use Observer as a 2D list .

As in => Observer = [ [Email,SMS,Phone] ]

* Don't write Email, SMS, Phone. As it interprets them as variables. Instead use some values or strings. as

'Email', 0 , 1, 2.

* You could pass another parameter for the attach and detach function.

* In attach function, you may Append the list instead of values. append([email,sms,phone])

SCREENSHOTS:

CODE:

class ServiceNotifier:
#Subject responsible for notifying registered observer objects
   Observer= [[],[]]
   # def __init__(self):
   #    self.Observer = [[],[]]
  
   def attach(self):
#add new observer
       self.Observer.append(insertnewobserverhere)

   def dettach(self):
#remove an observer
       self.Observer.pop(insertnewobserverhere)

   def servicenotifier(self):
       for observers in self.Observer:
           print("Due to the forecast for tomorrow, all university and campus operations will be closed.")
  

##########################################################

def Service():
#Main code to execute
   alerts = ServiceNotifier()
   notify = alerts.servicenotifier()
   return notify

if __name__ == "__main__":
#Exectues the weather alert system
   Service()

*Thank You*