MAINT: Add comment in dragon4 code.
MAINT: Add comment in dragon4 code.

[ci skip]
seberg/numpy,jorisvandenbossche/numpy,gfyoung/numpy,pdebuyl/numpy,rgommers/numpy,abalkin/numpy,pbrod/numpy,Eric89GXL/numpy,seberg/numpy,mattip/numpy,pbrod/numpy,pbrod/numpy,MSeifert04/numpy,grlee77/numpy,shoyer/numpy,numpy/numpy,MSeifert04/numpy,charris/numpy,MSeifert04/numpy,endolith/numpy,charris/numpy,ahaldane/numpy,ahaldane/numpy,ahaldane/numpy,gfyoung/numpy,Eric89GXL/numpy,jorisvandenbossche/numpy,abalkin/numpy,mattip/numpy,madphysicist/numpy,madphysicist/numpy,pizzathief/numpy,charris/numpy,mhvk/numpy,WarrenWeckesser/numpy,rgommers/numpy,Eric89GXL/numpy,anntzer/numpy,simongibbons/numpy,jakirkham/numpy,seberg/numpy,shoyer/numpy,rgommers/numpy,jorisvandenbossche/numpy,grlee77/numpy,pizzathief/numpy,mattip/numpy,pbrod/numpy,madphysicist/numpy,abalkin/numpy,madphysicist/numpy,simongibbons/numpy,jorisvandenbossche/numpy,seberg/numpy,jakirkham/numpy,endolith/numpy,anntzer/numpy,pdebuyl/numpy,rgommers/numpy,grlee77/numpy,numpy/numpy,jakirkham/numpy,grlee77/numpy,charris/numpy,simongibbons/numpy,pdebuyl/numpy,pizzathief/numpy,mhvk/numpy,MSeifert04/numpy,pizzathief/numpy,numpy/numpy,shoyer/numpy,mhvk/numpy,WarrenWeckesser/numpy,shoyer/numpy,pdebuyl/numpy,mhvk/numpy,jakirkham/numpy,mattip/numpy,anntzer/numpy,numpy/numpy,shoyer/numpy,jakirkham/numpy,anntzer/numpy,pbrod/numpy,endolith/numpy,jorisvandenbossche/numpy,WarrenWeckesser/numpy,simongibbons/numpy,madphysicist/numpy,endolith/numpy,WarrenWeckesser/numpy,grlee77/numpy,mhvk/numpy,MSeifert04/numpy,WarrenWeckesser/numpy,pizzathief/numpy,ahaldane/numpy,simongibbons/numpy,ahaldane/numpy,gfyoung/numpy,Eric89GXL/numpy