def is_tachy(patient):
    """Calculate if this patient has tachycardia or not based
    on the valu of heart rate

    If heart rate is larger than 100, it will return "tachycardic",
    otherwise, it will return "not tachycardic"

    :param patient: The data of a patient in JSON

    :returns: If heart rate is larger than 100, it will return "tachycardic",
    otherwise, it will return "not tachycardic"
    """
    if patient["heart_rate"][-1] >= 100:
        return "tachycardic"
    else:
        return "not tachycardic"