py-asterisk error from ExceptionBase need to provide a message

AsteriskUtil.py

# Asterisk/Util.py
class EventCollection(Logging.InstanceLogger):                                           
    '''                                                                                  
    Utility class to allow grouping and automatic registration of event.                 
    '''                                                                                  
                                                                                         
    def __init__(self, initial=None):                                                    
        '''                                                                              
        If <initial> is not None, register functions from the list <initial>             
        waiting for events with the same name as the function.                           
        '''                                                                              
                                                                                         
        self.subscriptions = {}                                                          
        self.log = self.getLogger()                                                      
                                                                                         
        if initial is not None:                                                          
            for func in initial:                                                         
                self.subscribe(func.__name__, func)                                      
                                                                                         
    def subscribe(self, name, handler):                                                  
        '''                                                                              
        Subscribe callable <handler> to event named <name>.                              
        '''                                                                              
                                                                                         
        if name not in self.subscriptions:                                               
            subscriptions = self.subscriptions[name] = []                                
        else:                                                                            
            subscriptions = self.subscriptions[name]                                     
                                                                                         
        if handler in subscriptions:                                                     
            raise SubscriptionError  # pylint: disable=W0710                             
                                                                                         
        subscriptions.append(handler)                                                    
                                                                                         

error poc

(felix) jorge@penta:~$ ipython
Python 3.9.2 (default, Feb 28 2021, 17:03:44) 
Type 'copyright', 'credits' or 'license' for more information
IPython 7.31.1 -- An enhanced Interactive Python. Type '?' for help.

In [1]: from Asterisk.Util import SubscriptionError

In [2]: SubscriptionError
Out[2]: Asterisk.Util.SubscriptionError

In [3]: raise SubscriptionError
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-3-d76b471ae3a5> in <module>
----> 1 raise SubscriptionError

TypeError: __init__() missing 1 required positional argument: 'error'

In [4]: 

Suscribing two times the same handler for an event, a SubscriptionError without explanation will be raised

if handler in subscriptions:                                                     
            raise SubscriptionError  # pylint: disable=W0710       

this error need to have a message

# Asterisk/__init__.py

class BaseException(Exception):                            
   '''                                                    
   Base class for all py-Asterisk exceptions.             
   '''                                                    
                                                          
   _prefix = '(Base Exception)'                           
   _error = '(no error)'                                  
                                                          
   def __init__(self, error):                             
       self._error = error