data types def escape_html(text)text text replace("&""&amp;"text text replace("<""&lt;"text text replace(">""&gt;"return text this function straightforwardly replaces each special html character with the appropriate html entity we must of course replace ampersands firstalthough the order doesn' matter for the angle brackets python' standard library includes slightly more sophisticated version of this function--you'll get the chance to use it in the exercisesand will see it again in summary ||this began by showing the list of python' keywords and described the rules that python applies to identifiers thanks to python' unicode supportidentifiers are not limited to subset of characters from small character set like ascii or latin- we also described python' int data typewhich differs from similar types in most other languages in that it has no intrinsic size limitation python integers can be as large as the machine' memory will allowand it is perfectly feasible to work with numbers that are hundreds of digits long all of python' most basic data types are immutablebut this is rarely noticable since the augmented assignment operators (+=*=-=/=and othersmeans that we can use very natural syntax while behind the scenes python creates result objects and rebinds our variables to them literal integers are usually written as decimal numbersbut we can write binary literals using the prefixoctal literals using the prefixand hexadecimal literals using the prefix when two integers are divided using /the result is always float this is different from many other widely used languagesbut helps to avoid some quite subtle bugs that can occur when division silently truncates (and if we want integer division we can use the /operator python has bool data type which can hold either true or false python has three logical operatorsandorand notof which the two binary operators (and and oruse short-circuit logic three kinds of floating-point numbers are availablefloatcomplexand decimal decimal the most commonly used is floatthis is double-precision floating-point number whose exact numerical characteristics depend on the underlying cc#or java library that python was built with complex numbers are represented as two floatsone holding the real value and the other the imaginary value the decimal decimal type is provided by the decimal module