being a presenter or copresenter of a proposal. '''

        u = user

        # User is a presenter

        user_is_presenter = Q(

            is_presenter=True,

            proposal_kind__proposalbase__presentation__speaker__user=u,

        )

        # User is a copresenter

        user_is_copresenter = Q(

            is_copresenter=True,

            proposal_kind__proposalbase__presentation__additional_speakers__user=u,  # NOQA

        )

        return queryset.filter(user_is_presenter | user_is_copresenter)

class GroupMemberConditionController(IsMetByFilter, ConditionController):

    @classmethod

    def pre_filter(self, conditions, user):

        ''' Returns all of the items from conditions which are enabled by a

        user being member of a Django Auth Group. '''