It looks like the first three commits are for a shiftdata fix you were preparing a month ago: it might be simplest to copy Downloads/.../solar.py somewhere, revert that commit, turn this PR into the shiftdata PR you were preparing, run git checkout upstream/develop -b flake8-solar-cleanup, copy solar.py back to packages/basemap/src/mpl_toolkits/basemap/solar.py, and open a new PR to be the "get flake8 to pipe down about solar.py" one

Alternately, you might be able to do

cd /path/to/basemap-repository/Downloads/basemap-develop/
git init
git remote add upstream https://github.com/matplotlib/basemap
git fetch upstream
git remote add origin git@github.com:Cdiaz1234/basemap
git fetch origin
git branch flake8-develop
cd packages/basemap/
git add src/mpl_toolkits/basemap/{__init__,solar}.py
git commit
git push --set-upstream --force origin flake8-develop

to turn the unpacked ZIP archive of the repository's develop branch into its own git repository