rapid introduction to procedural programming tupleslistsand strings are "sized"that isthey are data types that have notion of sizeand data items of any such data type can be meaningfully passed to the len(function (an exception is raised if nonsized data item is passed to len(all python data items are objects (also called instancesof particular data type (also called classwe will use the terms data type and class interchangeably one key difference between an objectand the plain items of data that some other languages provide ( +or java' built-in numeric types)is that an object can have methods essentiallya method is simply function that is called for particular object for examplethe list type has an append(methodso we can append an object to list like thisx ["zebra" - "aardvark" append("more" ['zebra' - 'aardvark' 'more'the object knows that it is list (all python objects know what their own data type is)so we don' need to specify the data type explicitly in the implementation of the append(method the first argument will be the object itself--this is done automatically by python as part of its syntactic support for methods the append(method mutatesthat ischangesthe original list this is possible because lists are mutable it is also potentially more efficient than creating new list with the original items and the extra item and then rebinding the object reference to the new listparticularly for very long lists in procedural language the same thing could be achieved by using the list' append(like this (which is perfectly valid python syntax)list append( "extra" ['zebra' - 'aardvark' 'more''extra'here we specify the data type and the data type' methodand give as the first argument the data item of the data type we want to call the method onfollowed by any additional arguments (in the face of inheritance there is subtle semantic difference between the two syntaxesthe first form is the one that is most commonly used in practice inheritance is covered in if you are unfamiliar with object-oriented programming this may seem bit strange at first for nowjust accept that python has conventional functions called like thisfunctionname(arguments)and methods which are called like thisobjectname methodname(arguments(object-oriented programming is covered in sized