How do I change elements in a list?

[Just Another Victim of the Ambient Morality]

    How do you change certain elements in a list?  I'm looking to do the 
Python equivalent of this Ruby code:


->  first = [1, 2]
=>  [1, 2]
->  second = first
=>  [1, 2]
->  first.map! {|i| i + 1}
=>  [2, 3]
->  first
=>  [2, 3]
->  second
=>  [2, 3]


    I need to change a list, in place, so other variables referencing that 
list also see the change.
    Thank you...