ENH: correlative Learn()
ENH: correlative Learn()

Do not bail out early with empty but not NULL input

naucoin/VTKSlicerWidgets,johnkit/vtk-dev,candy7393/VTK,sumedhasingla/VTK,SimVascular/VTK,mspark93/VTK,sumedhasingla/VTK,berendkleinhaneveld/VTK,aashish24/VTK-old,jmerkow/VTK,mspark93/VTK,Wuteyan/VTK,SimVascular/VTK,collects/VTK,naucoin/VTKSlicerWidgets,Wuteyan/VTK,arnaudgelas/VTK,gram526/VTK,ashray/VTK-EVM,collects/VTK,demarle/VTK,gram526/VTK,daviddoria/PointGraphsPhase1,demarle/VTK,gram526/VTK,johnkit/vtk-dev,gram526/VTK,demarle/VTK,mspark93/VTK,johnkit/vtk-dev,keithroe/vtkoptix,cjh1/VTK,arnaudgelas/VTK,cjh1/VTK,mspark93/VTK,collects/VTK,msmolens/VTK,naucoin/VTKSlicerWidgets,spthaolt/VTK,mspark93/VTK,hendradarwin/VTK,jeffbaumes/jeffbaumes-vtk,candy7393/VTK,hendradarwin/VTK,collects/VTK,jmerkow/VTK,collects/VTK,johnkit/vtk-dev,demarle/VTK,msmolens/VTK,jmerkow/VTK,demarle/VTK,keithroe/vtkoptix,SimVascular/VTK,jeffbaumes/jeffbaumes-vtk,ashray/VTK-EVM,aashish24/VTK-old,berendkleinhaneveld/VTK,aashish24/VTK-old,mspark93/VTK,sumedhasingla/VTK,biddisco/VTK,SimVascular/VTK,daviddoria/PointGraphsPhase1,demarle/VTK,biddisco/VTK,jeffbaumes/jeffbaumes-vtk,biddisco/VTK,aashish24/VTK-old,jmerkow/VTK,daviddoria/PointGraphsPhase1,cjh1/VTK,sankhesh/VTK,jeffbaumes/jeffbaumes-vtk,candy7393/VTK,berendkleinhaneveld/VTK,Wuteyan/VTK,gram526/VTK,jeffbaumes/jeffbaumes-vtk,Wuteyan/VTK,spthaolt/VTK,berendkleinhaneveld/VTK,sankhesh/VTK,demarle/VTK,candy7393/VTK,biddisco/VTK,SimVascular/VTK,daviddoria/PointGraphsPhase1,sankhesh/VTK,hendradarwin/VTK,collects/VTK,spthaolt/VTK,spthaolt/VTK,ashray/VTK-EVM,keithroe/vtkoptix,gram526/VTK,msmolens/VTK,msmolens/VTK,naucoin/VTKSlicerWidgets,keithroe/vtkoptix,naucoin/VTKSlicerWidgets,sankhesh/VTK,msmolens/VTK,daviddoria/PointGraphsPhase1,msmolens/VTK,SimVascular/VTK,cjh1/VTK,Wuteyan/VTK,biddisco/VTK,jmerkow/VTK,sankhesh/VTK,arnaudgelas/VTK,jmerkow/VTK,demarle/VTK,mspark93/VTK,berendkleinhaneveld/VTK,cjh1/VTK,aashish24/VTK-old,ashray/VTK-EVM,jmerkow/VTK,spthaolt/VTK,Wuteyan/VTK,ashray/VTK-EVM,sumedhasingla/VTK,sumedhasingla/VTK,arnaudgelas/VTK,johnkit/vtk-dev,johnkit/vtk-dev,hendradarwin/VTK,hendradarwin/VTK,jmerkow/VTK,arnaudgelas/VTK,candy7393/VTK,msmolens/VTK,berendkleinhaneveld/VTK,hendradarwin/VTK,cjh1/VTK,ashray/VTK-EVM,berendkleinhaneveld/VTK,candy7393/VTK,candy7393/VTK,daviddoria/PointGraphsPhase1,gram526/VTK,ashray/VTK-EVM,Wuteyan/VTK,sumedhasingla/VTK,naucoin/VTKSlicerWidgets,arnaudgelas/VTK,msmolens/VTK,sankhesh/VTK,sumedhasingla/VTK,SimVascular/VTK,ashray/VTK-EVM,hendradarwin/VTK,biddisco/VTK,keithroe/vtkoptix,spthaolt/VTK,jeffbaumes/jeffbaumes-vtk,keithroe/vtkoptix,sumedhasingla/VTK,keithroe/vtkoptix,sankhesh/VTK,biddisco/VTK,spthaolt/VTK,keithroe/vtkoptix,SimVascular/VTK,sankhesh/VTK,aashish24/VTK-old,candy7393/VTK,johnkit/vtk-dev,mspark93/VTK,gram526/VTK