def get_arrival(event, pickid):
    """Find the arrival object in a Catalog Event corresponding to input pick id.

    Args:
        event (Event): Obspy Catalog Event object.
        pickid (str): Pick ID string.

    Returns:
      Arrival: Obspy Catalog arrival object.
    """
    for origin in event.origins:
        idlist = [arr.pick_id for arr in origin.arrivals]
        if pickid not in idlist:
            continue
        idx = idlist.index(pickid)
        arrival = origin.arrivals[idx]
        return arrival
    if pickid is None:
        return None