def _disjunctive_union_strategy(ents):
    """This strategy ensures that all entities are disjoint.

    Checks that all entities are disjoint by comparing the end of the previous entity with the start of the current one.
    """
    prev_ent_end = 0
    for ent in ents:
        if prev_ent_end > ent.start_char:
            raise AssertionError(
                f"All entities were assumed to be disjunct, but {ent.text} ({ent.start_char}-{ent.end_char}) wasn't"
            )

        prev_ent_end = ent.end_char
    return ents