@staticmethod
def _iter_future_contradictions(entity, key, turns, branch, turn, tick, value):
    """If setting ``key=value`` would result in a contradiction, iterate over contradicted ``(turn, tick)``s."""
    if not turns:
        return
    if turn in turns:
        future_ticks = turns[turn].future(tick)
        for tck, newval in future_ticks.items():
            if newval != value:
                yield turn, tck
        future_turns = turns.future(turn)
    elif turns.rev_gettable(turn):
        future_turns = turns.future(turn)
    else:
        future_turns = turns
    if not future_turns:
        return
    for trn, ticks in future_turns.items():
        for tick, newval in ticks.items():
            if newval != value:
                yield trn, tick
