def assertDefaultTraceback(self, captureVars=False):
        """
        Assert that L{printTraceback} produces and prints a default traceback.

        The default traceback consists of a header::

          Traceback (most recent call last):

        The body with traceback::

          File "/twisted/trial/_synctest.py", line 1180, in _run
             runWithWarningsSuppressed(suppress, method)

        And the footer::

          --- <exception caught here> ---
            File "twisted/test/test_failure.py", line 39, in getDivisionFailure
              1/0
            exceptions.ZeroDivisionError: float division

        @param captureVars: Enables L{Failure.captureVars}.
        @type captureVars: C{bool}
        """
        if captureVars:
            exampleLocalVar = 'xyzzy'
            # Silence the linter as this variable is checked via
            # the traceback.
            exampleLocalVar

        f = getDivisionFailure(captureVars=captureVars)
        out = NativeStringIO()
        f.printTraceback(out)
        tb = out.getvalue()
        stack = ''
        for method, filename, lineno, localVars, globalVars in f.frames:
            stack += '  File "%s", line %s, in %s\n' % (filename, lineno,
                                                        method)
            stack += '    %s\n' % (linecache.getline(
                                   filename, lineno).strip(),)

        self.assertTracebackFormat(tb,
            "Traceback (most recent call last):",
            "%s\n%s%s: %s\n" % (failure.EXCEPTION_CAUGHT_HERE, stack,
            reflect.qual(f.type), reflect.safe_str(f.value)))

        if captureVars:
            self.assertIsNone(re.search('exampleLocalVar.*xyzzy', tb))

        Assert that L{printTraceback} produces and prints a default traceback.

        The default traceback consists of a header::

          Traceback (most recent call last):

        The body with traceback::

          File "/twisted/trial/_synctest.py", line 1180, in _run
             runWithWarningsSuppressed(suppress, method)

        And the footer::

          --- <exception caught here> ---
            File "twisted/test/test_failure.py", line 39, in getDivisionFailure
              1/0
            exceptions.ZeroDivisionError: float division

        @param captureVars: Enables L{Failure.captureVars}.
        @type captureVars: C{bool}
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_failure.py