def add_setting(settings, p):
    index = 1
    for string in p:
        low = string.lower()
        if index == 1:
            key = low
        else:
            value = low
        index += 1
    key_check = settings.get(key)
    if key_check != None:
        return f"Setting '{key}' already exists! Cannot add a new setting with this name."
    settings.setdefault(key, value)
    print(key, value)
    return f"Setting '{key}' added with value '{value}' successfully!"

def update_setting(settings, p):
    index = 1
    for string in p:
        low = string.lower()
        if index == 1:
            key = low
        else:
            value = low
        index += 1
    key_check = settings.get(key)
    if key_check == None:
        return f"Setting '{key}' does not exist! Cannot update a non-existing setting."
    settings[key] = value
    return f"Setting '{key}' updated to '{value}' successfully!"

def delete_setting(settings, k):
    key = k.lower()
    key_check = settings.get(key)
    if key_check == None:
        return "Setting not found!"
    settings.pop(key)
    return f"Setting '{key}' deleted successfully!"

def view_settings(settings):
    index = 1
    if settings == {}:
        return "No settings available."
    for keys, values in settings.items():
        key = keys.title()
        if index == 1:
            view = f"Current User Settings:\n"
            index += 1
        view += f"{key}: {values}\n"
    return view


test_settings = {
    "theme": "light",
    "notifications": "enabled",
    "filler": "Yes"
}
empty_settings = {}
print(add_setting(test_settings, ("volume", "High")))
print(update_setting(test_settings, ("theme", "DaRk")))
print(delete_setting(test_settings, "filler"))
print(view_settings(test_settings))
print(test_settings)