Final newline missing
Used when a Python source file has no line end character(s) on its last line.
This message belongs to the format checker.
While Python interpreters typically do not require line end character(s) on the last line, other programs processing Python source files may do, and it is simply good practice to have it. This is confirmed in Python docs: Line Structure which states that a physical line is ended by the respective line end character(s) of the platform.