[HELP] Function that changes its entrances

[Liquid]

Hello everyone,

I struggle with a python code. I found the problem and reproduced the condition of its occurence in the following lines:

def PLS(A):
    B = A
    B[0] = B[2]
    return(B)
    
A = [1,2,3]
D = PLS(A)
print(A)

Compiling those few lines, I expect D to be [2,3,2] and A to be [1,2,3].
Yet I get D = A = [2,3,2]

Why does the code modify the A list?
And how can I stop it from doing so?

I'm really thankful for any help, I've been stuck for a while on that :D