fig lower and upper bound consider the pylist append operation discussed earlier in this the latest version of the pylist append method simply calls the python append operation on lists python is implemented in it turns out that while python supports an append operation for listslists are implemented as arrays in and it is not possible to add to an array in an array can be allocated with fixed sizebut cannot have its size increased once created pretend for moment that python listslike arraysdid not support the append method on lists and that the only way to create list was to write something like [none]* where was fixed value writing [none]* creates fixed size list of elements each referencing the value none this is the way and +arrays are allocated in our examplesince we are pretending that python does not support append we must implement our pylist append method differently we can' use the append method and earlier in this we saw that that adding on item at time with the operator was bad idea we'll do something little different our pylist append operationwhen it runs out of space in the fixed size listwill double the size of the list copying all items from the old list to the new list as shown in the code in sect this copy belongs to 'acha