Update gui_setup.bat&sh: Check available Python version

gui_setup.bat

@@ -4,7 +4,37 @@ echo Installing PyPEF...
 set "python_exe=python"
 set "prefix="
 
-set /P AREYOUSURE=Install and use local Python version (Y/[N]) (downloads Python installer and installs Python locally in the current working directory)?
+for /F "delims=" %%i in ('powershell python --version') do set py_ver=%%i
+if not "%py_ver:~0,6%"=="Python" (
+    set "true=0"
+) else (
+    set "true=0"
+    if  "%py_ver:~7,5%"=="3.12." (
+        echo Found Python version 3.12.
+        set "true=1"        
+    )
+    if  "%py_ver:~7,5%"=="3.11." (
+        echo Found Python version 3.11.
+        set "true=1"
+    )
+    if  "%py_ver:~7,5%"=="3.10." (
+        echo Found Python version 3.10.
+        set "true=1"
+    )
+    if  "%py_ver:~7,4%"=="3.9." (
+        echo Found Python version 3.9.
+        set "true=1"
+    )
+)
+
+if "%true%"=="0" (
+    echo Did not find any Python version. Python will be installed locally in the next step...
+    set /P AREYOUSURE="Y"
+) else ( 
+    echo A suitable Python version was found, no local download and Python installtion should be necessary...
+    set /P AREYOUSURE="Install and use local Python version (Y/[N]) (downloads Python installer and installs Python locally in the current working directory)? "
+)
+
 if /I "%AREYOUSURE%" NEQ "Y" if /I "%AREYOUSURE%" NEQ "y" goto NO_PYTHON
 
 echo Installing Python...

gui_setup.sh

@@ -4,6 +4,13 @@ set -e
 # Only required for WSL(?):
 # sudo apt-get install -y libxcb-cursor-dev
 
+py_ver="$(python --version)"
+
+if [[ $py_ver == *"3.12."* ]] || [[ $py_ver == *"3.11."* ]] || [[ $py_ver == *"3.10."* ]] || [[ $py_ver == *"3.9."* ]]; then
+    echo "Identified Python version should be suitable for installing and running PyPEF..."
+else
+    echo >&2 "The identified Python version ($py_ver) does not match the required Python versions... you should activate/install a suitable version first, e.g. Python 3.12."; exit 1
+fi
 python -m pip install -U pypef pyside6
 
 printf "
@@ -25,4 +32,4 @@ echo "+++    run_pypef_gui.sh     +++"
 echo "+++ for future GUI starting +++"
 
 chmod a+x ./run_pypef_gui.sh
-./run_pypef_gui.sh && exit
+./run_pypef_gui.sh && exit 0