Interesting to see the module defines a pure Python implementation first, then tries to import a fast C implementation. If the C version is present, it replaces the Python version.
Bisect is a very old module, certainly present in Python 1.5.2 from 1999 that I started with. I expect the C implementations got added a year or two later.
Now I'm wondering - what is the point of the python version, if it will always be overridden by the C implementation? Are there circumstances (platforms, compile flags, ...) under which the C version would be unavailable when the python runtime is compiled?
It may be that other Python implementations use CPython's standard library, or at least part of it.
I think that PyPy in particular does this, but I'm not 100% sure. I know for certain that it uses pure Python implementation of some modules from somewhere. One program I took great pains to be PyPy compatible ended up being a lot slower in it, and it turned out to be that the built-in sqlite3 module has a C implementation in CPython that's faster than the pure-Python version even when runing in PyPy.
If binning data, discretize it and then use a dict lookup - `grades_to_letters[grade//10]`, for example.
For insort, and indeed anything with sorted collections, just use the http://www.grantjenks.com/docs/sortedcontainers/ module. Inserting an element is worst-case sublinear time, and also faster than C-extensions. It's one of the very few data-structure libraries I use regularly.
Short answer is no because we’re talking about asymptotic behavior and n dominates log n.
Long answer is yes because O notation is commonly written this way to be more illustrative of what’s happening in an algorithm and that were smushing to algorithms together.
If you can be more precise then feel free to write it down. For example O notation hides a constant factor but if you happen to actually know it exactly you might see O(7n) in the wild.