def METHOD_NAME(self):
    """Verify that a speaker is only shown once."""
    # Create a speaker with two accepted presentations.
    speaker = Speaker.objects.create(name="Two Accepted Presentations")
    Presentation.objects.create(
        slot=Slot.objects.create(
            day=self.day,
            kind=self.slot_kind,
            start=timezone.now(),
            end=timezone.now(),
        ),
        title="#1",
        description="Description",
        abstract="Abstract",
        speaker=speaker,
        proposal_base=ProposalBase.objects.create(
            title="#1",
            description="Description",
            abstract="Abstract",
            kind=self.proposal_kind,
            speaker=speaker,
        ),
        section=self.section,
    )
    Presentation.objects.create(
        slot=Slot.objects.create(
            day=self.day,
            kind=self.slot_kind,
            start=timezone.now(),
            end=timezone.now(),
        ),
        title="#2",
        description="Description",
        abstract="Abstract",
        speaker=speaker,
        proposal_base=ProposalBase.objects.create(
            title="#2",
            description="Description",
            abstract="Abstract",
            kind=self.proposal_kind,
            speaker=speaker,
        ),
        section=self.section,
    )
    self.assertEqual(speaker.presentations.count(), 2)
    response = self.client.get(reverse("speaker_list"))
    self.assertContains(response=response, text=speaker.name, count=1)