python 3 and PLEASE COMMENT YOUR WORK !

def remove_echo(xs): An echo is a contiguous sequence of identical values. Given xs as a list of values, this function returns a copy of xs with all but one value for each echo removed. o Assume: xs is a sequence of any length. o Restrictions: remember, you may not call index(): do not modify xs. remove_echo([1,1,3,3,3,2,1,2,2]) remove_echo ([1,3,2,1,2]) remove-echo( [ "B", "a","1","1","o", "o", "n"]) remove_echo([I) # no echo ["B", "a","1","o", "n"] [1 # a list of strings