Exception.py

#catch exception
    try :
        #throws exception if the input is not a number
        number = int(input())
        print(str(number))
    except ValueError:
        print('error in input')

printNumberInput()

#raise exception
def myFunction(symbol)
    if len(symbol) != 1 :
        raise Exception('The symbol lenght should be one')
    print(symbol)

#avoid to crash when we raise an exception but log all the
#errors as callstack to a separated log file
import traceback
try :
    raise Exception('Error message')
except :
    errorFile = open('error_log.txt','a')
    errorFile.write(traceback.format_exc())
    errorFile.close()
    print('wrote callstack to the error log file')



#assertion
assert False, 'exception message'  # they are threated as exception