[docs only] Pacify flake8
[docs only] Pacify flake8

oesteban/fmriprep,poldracklab/preprocessing-workflow,oesteban/preprocessing-workflow,poldracklab/fmriprep,oesteban/fmriprep,poldracklab/fmriprep,oesteban/fmriprep,poldracklab/preprocessing-workflow,oesteban/preprocessing-workflow,poldracklab/fmriprep