The Boredless Tourist - Add attraction Function

Hello Everyon.,
In the Boredless Tourist Project, Instruction 32

32.Append the attraction passed into add_attraction to the list attractions_for_destination.
That’s all we want this function to do, so we can return after adding the attraction to the list.

I wonder how/why to append a new item in a variable containing a sublist of the main list also add the new item in the main list, the code is as follows:

def add_attraction(destination, attraction):
destination_index=get_destination_index(destination)
attractions_for_the_destination=attractions[destination_index]
attractions_for_the_destination.append(attraction)
return attractions_for_the_destination

How is that the following code append a new attraction in both lists, “the attractions_for_the_destination” and the main list “attractions”
attractions_for_the_destination.append(attraction)
the append is over attractions_for_the_destination, I would think the attractions list wouldn’t be changed but it is, when I print attractions_for_the_destination and attractions both have the new item

I tested it with other lists and happened the same, append a new item in a variable containing a sublist of a main list adde the new item in both

Could someone explain the logic behind it?

Thanks everyone

I’m doing this project right now and have the same question.

Can anyone help?