can matter much in your programs for objects that support such in-place changesyou need to be more aware of shared referencessince change from one name may impact others otherwiseyour objects may seem to change for no apparent reason given that all assignments are based on references (including function argument passing)it' pervasive potential to illustratelet' take another look at the list objects introduced in recall that listswhich do support in-place assignments to positionsare simply collections of other objectscoded in square bracketsl [ here is list containing the objects and items inside list are accessed by their positionsso [ refers to object the first item in the list of courselists are also objects in their own rightjust like integers and strings after running the two prior assignmentsl and reference the same shared objectjust like and in the prior example (see figure - now say thatas beforewe extend this interaction to say the followingl this assignment simply sets to different objectl still references the original list if we change this statement' syntax slightlyhoweverit has radically different effectl [ [ mutable object make reference to the same object an in-place change [ [ is different but so is reallywe haven' changed itself herewe've changed component of the object that references this sort of change overwrites part of the list object' value in place because the list object is shared by (referenced fromother variablesthoughan inplace change like this doesn' affect only --that isyou must be aware that when you make such changesthey can impact other parts of your program in this examplethe effect shows up in as well because it references the same object as againwe haven' actually changed eitherbut its value will appear different because it refers to an object that has been overwritten in place this behavior only occurs for mutable objects that support in-place changesand is usually what you wantbut you should be aware of how it worksso that it' expected it' also just the defaultif you don' want such behavioryou can request that python copy objects instead of making references there are variety of ways to copy listincluding using the built-in list function and the standard library copy module perhaps the dynamic typing interlude