Event Sourcing with Python: How do I make a projection?

I'm trying to learn the event sourcing design pattern. And I am using the python eventsourcing library.

I've worked through the "Dog School" tutorial, but it isnt clear to me how to make a projection. I assume I need a projection if I want to retrieve a list of items in my aggregate?

It seems like projection is not in the library. Am I responsible for writing the queries to pull the data from persistence?

From the tutorial:

class DogSchool(Application):
    def register_dog(self, name):
        dog = Dog(name)
        self.save(dog)
        return dog.id

    def add_trick(self, dog_id, trick):
        dog = self.repository.get(dog_id)
        dog.add_trick(trick=trick)
        self.save(dog)

    def get_dog(self, dog_id):
        dog = self.repository.get(dog_id)
        return {'name': dog.name, 'tricks': tuple(dog.tricks)}

And I want a function like:

    def list_dogs(self):
        dogs = get_all_from_aggregate() #??
        return dogs

You don't need a projection to do this, but you could conceivably do it that way.

The documentation gives a Content management example that shows the basic the logic necessary to implement a list_dogs() method, without making a projection.

The heavy lifting is done by these methods in the example:

def _get_page_by_id(self, page_id: UUID) -> Page:
    return cast(Page, self.repository.get(page_id))

def get_pages(
    self,
    gt: Optional[int] = None,
    lte: Optional[int] = None,
    desc: bool = False,
    limit: Optional[int] = None,
) -> Iterator[PageDetailsType]:
    for page_logged in self.page_log.get(gt, lte, desc, limit):
        page = self._get_page_by_id(page_logged.page_id)
        yield self._details_from_page(page)

If you follow the example you should be able to create your list_dogs() method.