os and io classes that includes additional categories and granularity in xexception attributes must sometimes be inspected on system errors comparisons and sortsin xrelative magnitude comparisons of both mixedtypes and dictionaries are errorsand sorts do not support mixed types or general comparison functions (use key mappers insteadin all these forms work string exceptions and module functionsstring-based exceptions are fully removed in xthough they are also gone in as of (use classes insteadstring module functions redundant with string object methods are also removed in language removalsper table - removesrenamesor relocates many language itemsreloadapply` ` ldict has_keyraw_inputxrangefilereduceand file xreadlines -only extensions the following summarizes tools available in only extended sequence assignment allows in sequence assignment targets to collect remaining unmatched iterable items in list can achieve similar effects with slicing nonlocal provides nonlocal statementwhich allows names in enclosing function scopes to be changed from within nested functions can achieve similar effects with function attributesmutable objectsand class state function annotations allows function arguments and return types to be annotated with objects that are retained in the function but not otherwise used may often achieve similar effects with extra objects or decorator arguments keyword-only arguments allows specification of function arguments that must be passed as keywordstypically used for extra configuration options may often achieve similar effects with argument analysis and dictionary pops chained exceptions allows exceptions to be chained and thus appear in error messageswith raise from extension allows none to cancel the chain yield fromas of the yield statement may delegate to nested generator with from can often achieve similar results with for loop in simpler use cases namespace packagesas of the package model is extended to allow packages that span multiple directories with no initialization fileas fallback option might achieve similar effects with import extensions windows launcheras of launcher is shipped with python for windowsthough this is also available separately for use on other pythonsincluding internalsas of threading is implemented with time slices instead of virtual machine instruction countsand stores unicode text in variable-length major / differences