I am using Ubuntu 15.10 and Emacs 24. but recently when i open a Python source file in Emacs or create a new one, i get an error:
symbol's function definition is void: format-message
The file is opened as a Fundamental.
edit: this error only happens if i use my custom .emacs
file.
I asked the question in some IRC group's and came up with an answer... it seemed that elpa Python.el package, tries to load a file that is not python and is C++...
I just had to delete the file and it worked again.