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"""Observable base class for iterables.
For internal use only; no backwards-compatibility guarantees.
"""For internal use only; no backwards-compatibility guarantees.
An observable iterable.
Subclasses need to call self.notify_observers with any object yielded.
self.observers = 
[docs] def register_observer(self, callback):
[docs] def notify_observers(self, value, **kwargs):
# self.observers is almost always empty
for o in self.observers: