The codecs registry (as of 3.4) is unaware of two of the canonical encoding names from <https://encoding.spec.whatwg.org/#names-and-labels>: "windows-874" and "x-mac-cyrillic".  For interoperability's sake, please make these aliases for "cp874" and "mac_cyrillic" respectively.

(For full interop, *every* name and label in that list should be understood by str.encode(), but the canonical names are most useful.  Lack of support for iso-8859-i is already reported as https://bugs.python.org/issue18624 .  I have not tested the full set of non-canonical labels.)