def load_exemplars(exemplar_pre: dict) -> list:
    """ Load exemplar in previous cycle.
        Args:
            exemplar_pre (dict): Exemplars from previous cycle in the form of {item_id: [session, session,...], ...}
        Returns:
            exemplars (list): Exemplars list in the form of [session, session]
    """
    exemplars = []
    for item in exemplar_pre.values():
        if isinstance(item, list):
            exemplars.extend([i for i in item if i])
    return exemplars