def get_existing_symptoms(journal):
    """Given a journal w/ proper format, aggregates all the symptoms

    args:
        journal (dict)

    returns:
        [str]: array of symptom names
    """
    symptoms = []

    for log in journal['journal']:
        symptoms.extend([
            symptom['name'] for symptom in log['symptoms'] if symptom["name"] not in symptoms
        ])

    return symptoms