prints alternate nodes of a Linked List , first from head to end , and then from end to head .
def fun2 ( start ) : NEW_LINE INDENT if ( start == None ) : NEW_LINE INDENT return NEW_LINE DEDENT print ( start . data , end = " ▁ " ) NEW_LINE if ( start . next != None ) : NEW_LINE INDENT fun2 ( start . next . next ) NEW_LINE DEDENT print ( start . data , end = " ▁ " ) NEW_LINE DEDENT