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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def drop_temporary(pr: PullRequestDetails, problem: Optional[CannotAutomergeError], prev_seen_times: Dict[int, datetime.datetime], next_seen_times: Dict[int, datetime.datetime], ) -> Optional[CannotAutomergeError]: """Filters out problems that may be temporary."""


    if problem is not None and problem.may_be_temporary:
        since = prev_seen_times.get(pr.pull_id, datetime.datetime.utcnow())
        if is_recent_date(since):
            next_seen_times[pr.pull_id] = since
            return None

    return problem