4.x
Update python samples
Merge remote-tracking branch 'upstream/3.4' into merge-3.4
Merge pull request #17436 from vpisarev:fix_python_io
Merge pull request #17801 from LupusSanctus:am/pytorch_tf_segm
Merge pull request #16366 from themechanicalcoder:features2D-tutorial-python
samples: use findFile() in "python"
Update and expand erosion / dilation tutorial
Merge pull request #16889 from mehlukas:3.4-consolidateImshow
FIx misc. source and comment typos
photo: move TonemapDurand to opencv_contrib
Merge pull request #21224 from UncleLLD:fix-cvtColor-error