Okay. I just installed ROOT 6.22/00 (which I downloaded from https://github.com/root-project/root/tree/v6-22-00). Here is what I get on 64 bit Fedora 29 running `cmake version 3.14.5; gcc version 8.3.1; Python 2.7.17; Python 3.7.5:`

**FIRST**: With `"python3 demo.py"`

gives the following error:

```
enter "q" to quit: Traceback (most recent call last):
File "<string>", line 1, in <module>
NameError: name 'execfile' is not defined
enter "q" to quit: q
```

**SECOND**: With `"python2 demo.py" `

, I get the following error:

```
enter "q" to quit: input_line_58:1:64: error: redefinition of 'is_equal'
namespace __cppyy_internal { template<class C1, class C2> bool is_equal(const C1& c1, const C2& c2) { return (bool)(c1 == c2); } }
^
input_line_9:1:64: note: previous definition is here
namespace __cppyy_internal { template<class C1, class C2> bool is_equal(const C1& c1, const C2& c2) { return (bool)(c1 == c2); } }
^
input_line_59:1:64: error: redefinition of 'is_not_equal'
namespace __cppyy_internal { template<class C1, class C2> bool is_not_equal(const C1& c1, const C2& c2) { return (bool)(c1 != c2); } }
^
input_line_10:1:64: note: previous definition is here
namespace __cppyy_internal { template<class C1, class C2> bool is_not_equal(const C1& c1, const C2& c2) { return (bool)(c1 != c2); } }
^
*** Break *** segmentation violation
===========================================================
There was a crash.
This is the entire stack trace of all threads:
===========================================================
Thread 2 (Thread 0x7f51f1728700 (LWP 31810)):
#0 0x00007f520a0fe472 in waitpid () from /lib64/libc.so.6
#1 0x00007f520a07983f in do_system () from /lib64/libc.so.6
#2 0x00007f51fcc00ff3 in TUnixSystem::StackTrace() () from /home/ajay/Downloads/root_6.22/lib/libCore.so
#3 0x00007f51f00a7c5d in (anonymous namespace)::TExceptionHandlerImp::HandleException(int) () from /home/ajay/Downloads/root_6.22/lib/libcppyy_backend3_7.so
#4 0x00007f51fcc030fd in TUnixSystem::DispatchSignals(ESignals) () from /home/ajay/Downloads/root_6.22/lib/libCore.so
#5 <signal handler called>
#6 0x00007f520a49019c in PyUnicodeUCS4_Compare () from /lib64/libpython2.7.so.1.0
#7 0x00007f520a490001 in PyUnicodeUCS4_RichCompare () from /lib64/libpython2.7.so.1.0
#8 0x00007f520a46f773 in try_rich_compare () from /lib64/libpython2.7.so.1.0
#9 0x00007f520a46ebe6 in PyObject_RichCompare () from /lib64/libpython2.7.so.1.0
#10 0x00007f520a46ea43 in PyObject_RichCompareBool () from /lib64/libpython2.7.so.1.0
#11 0x00007f520a4599bd in list_contains () from /lib64/libpython2.7.so.1.0
#12 0x00007f51f01b5417 in TPyClassGenerator::GetClass(char const*, bool, bool) () from /home/ajay/Downloads/root_6.22/lib/libROOTTPython.so
#13 0x00007f51fcba3887 in TClass::LoadClassCustom(char const*, bool) () from /home/ajay/Downloads/root_6.22/lib/libCore.so
#14 0x00007f51fcbad227 in TClass::GetClass(char const*, bool, bool) () from /home/ajay/Downloads/root_6.22/lib/libCore.so
#15 0x00007f51fcbadecc in TClass::InheritsFrom(char const*) const () from /home/ajay/Downloads/root_6.22/lib/libCore.so
#16 0x00007f51eb77ab48 in TASImage::InitVisual() () from /home/ajay/Downloads/root_6.22/lib/libASImage.so
#17 0x00007f51eb78078e in TASImage::ReadImage(char const*, TImage::EImageFileTypes) () from /home/ajay/Downloads/root_6.22/lib/libASImage.so
#18 0x00007f51f0d47000 in TImage::Open(char const*, TImage::EImageFileTypes) () from /home/ajay/Downloads/root_6.22/lib/libGraf.so
#19 0x00007f51ebe31784 in TGPicturePool::GetPicture(char const*) () from /home/ajay/Downloads/root_6.22/lib/libGui.so
#20 0x00007f51ebe384d2 in TGHScrollBar::TGHScrollBar(TGWindow const*, unsigned int, unsigned int, unsigned int, unsigned long) () from /home/ajay/Downloads/root_6.22/lib/libGui.so
#21 0x00007f51ebd89ad9 in TGCanvas::TGCanvas(TGWindow const*, unsigned int, unsigned int, unsigned int, unsigned long) () from /home/ajay/Downloads/root_6.22/lib/libGui.so
#22 0x00007f51ebeac7d2 in TRootCanvas::CreateCanvas(char const*) () from /home/ajay/Downloads/root_6.22/lib/libGui.so
#23 0x00007f51ebead53c in TRootCanvas::TRootCanvas(TCanvas*, char const*, int, int, unsigned int, unsigned int) () from /home/ajay/Downloads/root_6.22/lib/libGui.so
#24 0x00007f51ebeb9d2e in TRootGuiFactory::CreateCanvasImp(TCanvas*, char const*, int, int, unsigned int, unsigned int) () from /home/ajay/Downloads/root_6.22/lib/libGui.so
#25 0x00007f51f0e5f3f7 in TCanvas::Constructor(char const*, char const*, int, int, int, int) () from /home/ajay/Downloads/root_6.22/lib/libGpad.so
#26 0x00007f51f0e6151f in TCanvas::TCanvas(char const*, char const*, int, int, int, int) () from /home/ajay/Downloads/root_6.22/lib/libGpad.so
#27 0x00007f51fc92509c in ?? ()
#28 0x00007f51000001f4 in ?? ()
#29 0x000000000000024b in ?? ()
#30 0x000000000000024b in ?? ()
#31 0x00007f51ec0890e0 in ?? ()
#32 0x00007f51f0e61430 in ?? () from /home/ajay/Downloads/root_6.22/lib/libGpad.so
#33 0x00007f51ec0890e0 in ?? ()
#34 0x00007f51ec0011a0 in ?? ()
#35 0x58e3147e98638600 in ?? ()
#36 0x00007f51f1725908 in ?? ()
#37 0x00007f51f1725880 in ?? ()
#38 0x0000000600000006 in ?? ()
#39 0x0000000000000000 in ?? ()
Thread 1 (Thread 0x7f520a033580 (LWP 31780)):
#0 0x00007f520a122f94 in read () from /lib64/libc.so.6
#1 0x00007f520a0b2c98 in __GI__IO_file_underflow () from /lib64/libc.so.6
#2 0x00007f520a0b3dd6 in _IO_default_uflow () from /lib64/libc.so.6
#3 0x00007f520a0a722a in _IO_getline_info () from /lib64/libc.so.6
#4 0x00007f520a0a623f in fgets () from /lib64/libc.so.6
#5 0x00007f520a3ed4bc in my_fgets () from /lib64/libpython2.7.so.1.0
#6 0x00007f520a3ed375 in PyOS_StdioReadline () from /lib64/libpython2.7.so.1.0
#7 0x00007f520a3ed2e2 in PyOS_Readline () from /lib64/libpython2.7.so.1.0
#8 0x00007f520a41d16b in builtin_raw_input.cold () from /lib64/libpython2.7.so.1.0
#9 0x00007f520a516915 in PyEval_EvalFrameEx () from /lib64/libpython2.7.so.1.0
#10 0x00007f520a517162 in PyEval_EvalCodeEx () from /lib64/libpython2.7.so.1.0
#11 0x00007f520a5173fd in PyEval_EvalCode () from /lib64/libpython2.7.so.1.0
#12 0x00007f520a51d4bf in run_mod () from /lib64/libpython2.7.so.1.0
#13 0x00007f520a51d464 in PyRun_FileExFlags () from /lib64/libpython2.7.so.1.0
#14 0x00007f520a51d27c in PyRun_SimpleFileExFlags () from /lib64/libpython2.7.so.1.0
#15 0x00007f520a522f08 in Py_Main () from /lib64/libpython2.7.so.1.0
#16 0x00007f520a058413 in __libc_start_main () from /lib64/libc.so.6
#17 0x0000561fd85110ae in _start ()
===========================================================
The lines below might hint at the cause of the crash.
You may get help by asking at the ROOT forum http://root.cern.ch/forum
Only if you are really convinced it is a bug in ROOT then please submit a
report at http://root.cern.ch/bugs Please post the ENTIRE stack trace
from above as an attachment in addition to anything else
that might help us fixing this issue.
===========================================================
#6 0x00007f520a49019c in PyUnicodeUCS4_Compare () from /lib64/libpython2.7.so.1.0
#7 0x00007f520a490001 in PyUnicodeUCS4_RichCompare () from /lib64/libpython2.7.so.1.0
#8 0x00007f520a46f773 in try_rich_compare () from /lib64/libpython2.7.so.1.0
#9 0x00007f520a46ebe6 in PyObject_RichCompare () from /lib64/libpython2.7.so.1.0
#10 0x00007f520a46ea43 in PyObject_RichCompareBool () from /lib64/libpython2.7.so.1.0
#11 0x00007f520a4599bd in list_contains () from /lib64/libpython2.7.so.1.0
#12 0x00007f51f01b5417 in TPyClassGenerator::GetClass(char const*, bool, bool) () from /home/ajay/Downloads/root_6.22/lib/libROOTTPython.so
#13 0x00007f51fcba3887 in TClass::LoadClassCustom(char const*, bool) () from /home/ajay/Downloads/root_6.22/lib/libCore.so
#14 0x00007f51fcbad227 in TClass::GetClass(char const*, bool, bool) () from /home/ajay/Downloads/root_6.22/lib/libCore.so
#15 0x00007f51fcbadecc in TClass::InheritsFrom(char const*) const () from /home/ajay/Downloads/root_6.22/lib/libCore.so
#16 0x00007f51eb77ab48 in TASImage::InitVisual() () from /home/ajay/Downloads/root_6.22/lib/libASImage.so
#17 0x00007f51eb78078e in TASImage::ReadImage(char const*, TImage::EImageFileTypes) () from /home/ajay/Downloads/root_6.22/lib/libASImage.so
#18 0x00007f51f0d47000 in TImage::Open(char const*, TImage::EImageFileTypes) () from /home/ajay/Downloads/root_6.22/lib/libGraf.so
#19 0x00007f51ebe31784 in TGPicturePool::GetPicture(char const*) () from /home/ajay/Downloads/root_6.22/lib/libGui.so
#20 0x00007f51ebe384d2 in TGHScrollBar::TGHScrollBar(TGWindow const*, unsigned int, unsigned int, unsigned int, unsigned long) () from /home/ajay/Downloads/root_6.22/lib/libGui.so
#21 0x00007f51ebd89ad9 in TGCanvas::TGCanvas(TGWindow const*, unsigned int, unsigned int, unsigned int, unsigned long) () from /home/ajay/Downloads/root_6.22/lib/libGui.so
#22 0x00007f51ebeac7d2 in TRootCanvas::CreateCanvas(char const*) () from /home/ajay/Downloads/root_6.22/lib/libGui.so
#23 0x00007f51ebead53c in TRootCanvas::TRootCanvas(TCanvas*, char const*, int, int, unsigned int, unsigned int) () from /home/ajay/Downloads/root_6.22/lib/libGui.so
#24 0x00007f51ebeb9d2e in TRootGuiFactory::CreateCanvasImp(TCanvas*, char const*, int, int, unsigned int, unsigned int) () from /home/ajay/Downloads/root_6.22/lib/libGui.so
#25 0x00007f51f0e5f3f7 in TCanvas::Constructor(char const*, char const*, int, int, int, int) () from /home/ajay/Downloads/root_6.22/lib/libGpad.so
#26 0x00007f51f0e6151f in TCanvas::TCanvas(char const*, char const*, int, int, int, int) () from /home/ajay/Downloads/root_6.22/lib/libGpad.so
#27 0x00007f51fc92509c in ?? ()
#28 0x00007f51000001f4 in ?? ()
#29 0x000000000000024b in ?? ()
#30 0x000000000000024b in ?? ()
#31 0x00007f51ec0890e0 in ?? ()
#32 0x00007f51f0e61430 in ?? () from /home/ajay/Downloads/root_6.22/lib/libGpad.so
#33 0x00007f51ec0890e0 in ?? ()
#34 0x00007f51ec0011a0 in ?? ()
#35 0x58e3147e98638600 in ?? ()
#36 0x00007f51f1725908 in ?? ()
#37 0x00007f51f1725880 in ?? ()
#38 0x0000000600000006 in ?? ()
#39 0x0000000000000000 in ?? ()
===========================================================
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "demoshelp.py", line 16, in <module>
chelp = TCanvas( 'chelp', 'Help to run demos', 200, 10, 700, 500 )
TypeError: none of the 5 overloaded methods succeeded. Full details:
TCanvas::TCanvas(bool build = kTRUE) =>
TypeError: takes at most 1 arguments (6 given)
TCanvas::TCanvas(const char* name, const char* title, int ww, int wh) =>
TypeError: takes at most 4 arguments (6 given)
TCanvas::TCanvas(const char* name, const char* title, int wtopx, int wtopy, int ww, int wh) =>
SegmentationViolation: segfault in C++; program state was reset
TCanvas::TCanvas(const char* name, int ww, int wh, int winid) =>
TypeError: takes at most 4 arguments (6 given)
TCanvas::TCanvas(const char* name, const char* title = "", int form = 1) =>
TypeError: takes at most 3 arguments (6 given)
https://github.com/root-project/root/tree/v6-22-00https://github.com/root-project/root/tree/v6-22-00
```

Is this a known bug or I am doing something wrong? Or some package incompatibility issue?