[Tutor] Best practice for API design handeling collections and single objects

[Knacktus]

Hi all,

I've got a question for you about how to best design an API that has to 
handle requests for single objects and collections of those objects.

My naming conventions are: Plural nouns for collections, singular nouns 
for single objects. "Key_to_value"-style for dictionaries. So I normaly 
know in my code wether I'm handling collections, dicts or single types.

So, here's an simplified example:
#-----------------------------------------------------------------------
class Meals(object):

     def __init__(self, id_on_menu_to_meal):
         self.id_on_menu_to_meal = id_on_menu_to_meal

#-----------------------------------------------------------------------

Now I need to return one meal by one id_on_menu and also several meals 
by several ids_on_menu.

I can think of three options:

1) create two methods:
#-----------------------------------------------------------------------
     def get_meal_by_ident(self, ident):
         return self.id_on_menu_to_meal[ident]

     def get_meals_by_idents(self, idents):
         return [self.get_meal_by_ident(ident) for ident in idents]

#-----------------------------------------------------------------------


2) create one method, which is smart enough to discriminate between the 
input (having fun with the naming conventions ;-)):
#-----------------------------------------------------------------------
     def get_meal_or_meals_by_ident_or_idents(self, ident_or_idents):
         try:
             return self.id_on_menu_to_meal[ident_or_idents]
         except KeyError:
             return [self.id_on_menu_to_meal[ident] for
                     ident in ident_or_idents]

#-----------------------------------------------------------------------


3) handle by convention application-wide only collections:
#-----------------------------------------------------------------------
     def get_meals_by_idents(self, idents):
         return [self.id_on_menu_to_meal[ident] for ident in idents]

#-----------------------------------------------------------------------

Without having too much experience on things like that, my gut feeling 
tells me to use option 1). What would you guys consider as a best 
practice here?

Thanks in advance and cheers,

Jan