'Format and return the specified exception information as a string.
This default implementation just uses
traceback.print_exception()'

def formatException(self, ei):

    sio = io.StringIO()
    tb = ei[2]
    traceback.print_exception(ei[0], ei[1], tb, None, sio)
    s = sio.getvalue()
    sio.close()
    if (s[(-1):] == '\n'):
        s = s[:(-1)]
    return s
