"Error in sys.excepthook" PyQt5.10.1Python 3.6 - pyqt5

Question

i have a custom sys.excepthook in my main.py:
def application_exception_hook(type_, value, tb):
lines = format_exception(type_, value, tb)
for line in lines:
print(line)
sys.excepthook = sys._excepthook
sys.exit(1)
sys._excepthook = sys.excepthook
sys.excepthook = application_exception_hook
In case of a unhandled exception the console output is:
Traceback (most recent call last):
Error in sys.excepthook:
Traceback (most recent call last):
Original exception was:
Traceback (most recent call last):
Replacing...
for line in lines:
print(line)
...with...
print(lines)
...gives me this output:
['Traceback (most recent call last):\n', ' File "D:\\...\\framework.py", line 144, in openNesting\n foo = 123 / 0\n', 'ZeroDivisionError: division by zero\n']Error in sys.excepthook:
Traceback (most recent call last):
Original exception was:
Traceback (most recent call last):
So, in both cases there is an "Error in sys.excepthook", while in the first case the error already appears before printing out all the interesting attributes. I would like to know what could cause "Error in sys.excepthook" and how I can get ONLY this output:
Traceback (most recent call last):
File "D:\\...\\framework.py", line 144, in openNesting
foo = 123 / 0
ZeroDivisionError: division by zero
I could not find any solved topic adressing this specific problem.

Answer 1

Solved: There was an error in a method that duplicates stdout and stderr messages to a QtTextEdit. After manually tracing it down everything now works as expected.