fix: doctest imports in preprocessing workflows
fix: doctest imports in preprocessing workflows

FCP-INDI/nipype,wanderine/nipype,wanderine/nipype,FCP-INDI/nipype,blakedewey/nipype,grlee77/nipype,mick-d/nipype_source,pearsonlab/nipype,carolFrohlich/nipype,glatard/nipype,mick-d/nipype,dmordom/nipype,rameshvs/nipype,sgiavasis/nipype,dgellis90/nipype,sgiavasis/nipype,sgiavasis/nipype,pearsonlab/nipype,gerddie/nipype,JohnGriffiths/nipype,mick-d/nipype_source,rameshvs/nipype,mick-d/nipype,grlee77/nipype,glatard/nipype,mick-d/nipype,carlohamalainen/nipype,rameshvs/nipype,rameshvs/nipype,carolFrohlich/nipype,FCP-INDI/nipype,iglpdc/nipype,arokem/nipype,gerddie/nipype,christianbrodbeck/nipype,glatard/nipype,grlee77/nipype,iglpdc/nipype,arokem/nipype,arokem/nipype,fprados/nipype,blakedewey/nipype,iglpdc/nipype,Leoniela/nipype,JohnGriffiths/nipype,dgellis90/nipype,mick-d/nipype_source,Leoniela/nipype,carolFrohlich/nipype,wanderine/nipype,gerddie/nipype,iglpdc/nipype,carlohamalainen/nipype,fprados/nipype,arokem/nipype,JohnGriffiths/nipype,pearsonlab/nipype,FCP-INDI/nipype,mick-d/nipype,FredLoney/nipype,FredLoney/nipype,FredLoney/nipype,dmordom/nipype,blakedewey/nipype,glatard/nipype,christianbrodbeck/nipype,fprados/nipype,dgellis90/nipype,carlohamalainen/nipype,JohnGriffiths/nipype,sgiavasis/nipype,pearsonlab/nipype,gerddie/nipype,blakedewey/nipype,grlee77/nipype,carolFrohlich/nipype,wanderine/nipype,dgellis90/nipype,dmordom/nipype,Leoniela/nipype