def strip_stac_item(item: dict) -> dict:
    """
    Strips a stac item, removing not stored fields

    :param item dict: input stac item
    :rtype: dict
    :return: stripped stac item
    """

    strip = item
    s3_key = None
    for link in item["links"]:
        if link["rel"] == "self":
            s3_key = link["href"]
    assert s3_key is not None, "Can't find self key"
    # Remove fields that will not be stored
    strip.pop("stac_version")
    strip.pop("stac_extensions")
    strip.pop("type")
    strip.pop("links")
    strip.pop("bbox")
    strip.pop("assets")

    # https://cbers-stac-0-6.s3.amazonaws.com/CBERS4/PAN5M/156/107/CBERS_4_PAN5M_20150610_156_107_L4.json
    strip["s3_key"] = "/".join(s3_key.split("/")[3:])

    return strip