old_contents: from axis import RegularAxis, Axis
  from coordinate_system import VoxelCoordinateSystem, DiagonalCoordinateSystem
  from mapping import Affine
  
  
  # MNI template axes
  MNI = (
    RegularAxis(name='zspace', length=109, start=-72., step=2.0),
    RegularAxis(name='yspace', length=109, start=-126., step=2.0),
    RegularAxis(name='xspace', length=91, start=-90., step=2.0))
  
  # Default axes
  generic = (
    Axis(name='zspace'),
    Axis(name='yspace'),
    Axis(name='xspace'))
  
  # Standard coordinates for MNI template
  MNI_voxel = VoxelCoordinateSystem(
    'MNI_voxel', generic, [dim.length for dim in MNI])
  MNI_world = DiagonalCoordinateSystem('MNI_world', MNI)
  
  MNI_mapping = Affine(MNI_voxel, MNI_world, MNI_world.transform())
  
  
new_contents: from axis import RegularAxis, Axis, generic
  from coordinate_system import VoxelCoordinateSystem, DiagonalCoordinateSystem
  from mapping import Affine
  
  
  # MNI template axes
  MNI = (
    RegularAxis(name='zspace', length=109, start=-72., step=2.0),
    RegularAxis(name='yspace', length=109, start=-126., step=2.0),
    RegularAxis(name='xspace', length=91, start=-90., step=2.0))
  
  
  # Standard coordinates for MNI template
  MNI_voxel = VoxelCoordinateSystem(
    'MNI_voxel', generic, [dim.length for dim in MNI])
  MNI_world = DiagonalCoordinateSystem('MNI_world', MNI)
  
  MNI_mapping = Affine(MNI_voxel, MNI_world, MNI_world.transform())
  
  
subject: move 'generic' from mni.py to axis.py