Iterator Method: provides a way to access the elements of an aggregate object sequentially without exposing its underlying representation.

Python requires only the __iter__() method to be implemented for an object to return True to isinstance(obj, Iterable), however if an object implements just the __getitem__() without __iter__ method then it will work as an iterable!

Composite Pattern: allows you to compose objects into tree structures to represent whole-part hierarchies. Composite lets clients treat individual objects and compositions of objects uniformly.

A pythonic alternative would be to:

try: 
    composition_method()
except CompositionMethodError:
    individual_method()