Protect PyMva tutorials for a failurte in importing tensorflow

Disable also batchgenerator tests for Python version less than 3.9 since tensorflow is not working for these lower python versions

Author: lmoneta

bindings/pyroot/pythonizations/test/CMakeLists.txt

@@ -191,6 +191,6 @@ ROOT_ADD_PYUNITTEST(pyroot_memory memory.py)
 # rbatchgenerator tests
 # TODO: We currently do not support TensorFlow for Python >= 3.12 (see requirements.txt)
 # Update here once that is fixed.
-if (NOT MSVC AND Python3_VERSION VERSION_LESS 3.12)
+if (NOT MSVC AND tmva)
   ROOT_ADD_PYUNITTEST(batchgen rbatchgenerator_completeness.py PYTHON_DEPS numpy tensorflow torch)
 endif()

tutorials/machine_learning/TMVA_CNN_Classification.py

@@ -37,7 +37,11 @@
     useKerasCNN = False
     print("TMVA_CNN_Classificaton","Skip using Keras since tensorflow is not installed")
 else:
-    import tensorflow
+    try:
+      import tensorflow
+    except:
+      ROOT.Warning("TMVA_CNN_Classification", "Skip using Keras since tensorflow cannot be imported")
+      useKerasCNN = False
 
 # PyTorch has to be imported before ROOT to avoid crashes because of clashing
 # std::regexp symbols that are exported by cppyy.
@@ -47,7 +51,11 @@
     usePyTorchCNN = False
     print("TMVA_CNN_Classificaton","Skip using PyTorch since torch is not installed")
 else:
-    import torch
+    try:
+      import torch
+    except:
+      ROOT.Warning("TMVA_CNN_Classification", "Skip using PyTorch since it cannot be imported")
+      usePyTorchCNN = False
 
 
 import ROOT

tutorials/machine_learning/TMVA_RNN_Classification.py

@@ -160,8 +160,14 @@ def MakeTimeData(n, ntime, ndim):
 
 tf_spec = importlib.util.find_spec("tensorflow")
 if tf_spec is None:
-    useKeras = False
-    ROOT.Warning("TMVA_RNN_Classificaton","Skip using Keras since tensorflow is not installed")
+   useKeras = False
+   ROOT.Warning("TMVA_RNN_Classificaton","Skip using Keras since tensorflow is not installed")
+else:
+   try:
+      import tensorflow
+   except:
+      ROOT.Warning("TMVA_RNN_Classification", "Skip using Keras since tensorflow cannot be imported")
+      useKeras = False
 
 
 rnn_types = ["RNN", "LSTM", "GRU"]