import json


def lookup_alt(alt: int) -> list:
    """

    This function looks into the performance file and extracts the list of lists corresponding to presettings
    corresponding to the specified altitude
    :param alt: cruise altitude (0 to 15000)
    :return: a list of lists corresponding of all altitude presettings
    """
    key = alt - alt % 2500
    if key == 0:
        key = 2500
    with open('performance.txt') as f:
        file = f.read()
    perf_dict = json.loads(file)
    return perf_dict[str(key)]