As of 3.7 [1], dict is guaranteed to preserve insertion order:  the insertion-order preservation nature of dict  objects has been declared to be an official part  of the Python language spec.However, at least one key part of the language reference [2] was not updated to reflect this:  "3.2. The standard type hierarchy" > "Mappings" > "Dictionaries".Note that the library docs [3] *were* updated.[1]https://docs.python.org/3/whatsnew/3.7.html#summary-release-highlights[2]https://docs.python.org/3/reference/datamodel.html#index-30[3]https://docs.python.org/3/library/stdtypes.html#typesmapping