old_contents: from .complex_circle import ComplexCircle
  from .euclidean import Euclidean, SkewSymmetric, Symmetric
  from .fixed_rank import FixedRankEmbedded
  from .grassmann import Grassmann
  from .oblique import Oblique
  from .product import Product
  from .psd import (Elliptope, SymmetricPositiveDefinite, PSDFixedRank,
                    PSDFixedRankComplex)
  from .rotations import Rotations
  from .sphere import (Sphere, SphereSubspaceComplementIntersection,
                       SphereSubspaceIntersection)
  from .stiefel import Stiefel
  
new_contents: from .complex_circle import ComplexCircle
  from .euclidean import Euclidean, SkewSymmetric, Symmetric
  from .fixed_rank import FixedRankEmbedded
  from .grassmann import Grassmann
  from .oblique import Oblique
  from .product import Product
  from .psd import (Elliptope, SymmetricPositiveDefinite, PSDFixedRank,
                    PSDFixedRankComplex)
  from .rotations import Rotations
  from .sphere import (Sphere, SphereSubspaceComplementIntersection,
                       SphereSubspaceIntersection)
  from .stiefel import Stiefel
  
  
  __all__ = (
      "ComplexCircle",
      "Euclidean",
      "SkewSymmetric",
      "Symmetric",
      "FixedRankEmbedded",
      "Grassmann",
      "Oblique",
      "Product",
      "Elliptope",
      "SymmetricPositiveDefinite",
      "PSDFixedRank",
      "PSDFixedRankComplex",
      "Rotations",
      "Sphere",
      "SphereSubspaceComplementIntersection",
      "SphereSubspaceIntersection",
      "Stiefel"
  )
  
subject: add '__all__' variable again for pydoc