open(function file-like object synonym for file object finder an object that tries to find the loader for module that is being imported since python there are two types of findermeta path finders for use with sys meta_pathand path entry finders for use with sys path_hooks see pep pep and pep for much more detail floor division mathematical division that rounds down to nearest integer the floor division operator is /for examplethe expression / evaluates to in contrast to the returned by float true division note that (- / is - because that is - rounded downward see pep function series of statements which returns some value to caller it can also be passed zero or more arguments which may be used in the execution of the body see also parametermethodand the function section function annotation an annotation of function parameter or return value function annotations are usually used for type hintsfor example this function is expected to take two int arguments and is also expected to have an int return valuedef sum_two_numbers(aintbint-intreturn function annotation syntax is explained in section function see variable annotation and pep which describe this functionality __future__ pseudo-module which programmers can use to enable new language features which are not compatible with the current interpreter by importing the __future__ module and evaluating its variablesyou can see when new feature was first added to the language and when it becomes the defaultimport __future__ __future__ division _feature(( 'alpha' )( 'alpha' ) garbage collection the process of freeing memory when it is not used anymore python performs garbage collection via reference counting and cyclic garbage collector that is able to detect and break reference cycles the garbage collector can be controlled using the gc module generator function which returns generator iterator it looks like normal function except that it contains yield expressions for producing series of values usable in for-loop or that can be retrieved one at time with the next(function usually refers to generator functionbut may refer to generator iterator in some contexts in cases where the intended meaning isn' clearusing the full terms avoids ambiguity generator iterator an object created by generator function each yield temporarily suspends processingremembering the location execution state (including local variables and pending try-statementswhen the generator iterator resumesit picks up where it left off (in contrast to functions which start fresh on every invocationgenerator expression an expression that returns an iterator it looks like normal expression followed by for expression defining loop variablerangeand an optional if expression the combined expression generates values for an enclosing functionsum( * for in range( ) sum of squares