How to use the pydevd._CustomWriter function in pydevd

def init_stderr_redirect(on_write=None):
    if not hasattr(sys, '_pydevd_err_buffer_'):
        wrap_buffer = True if not IS_PY2 else False
        original = sys.stderr
        sys._pydevd_err_buffer_ = _CustomWriter(2, original, wrap_buffer, on_write)
        sys.stderr_original = original
        sys.stderr = pydevd_io.IORedirector(original, sys._pydevd_err_buffer_, wrap_buffer)  # @UndefinedVariable

def init_stdout_redirect(on_write=None):
    if not hasattr(sys, '_pydevd_out_buffer_'):
        wrap_buffer = True if not IS_PY2 else False
        original = sys.stdout
        sys._pydevd_out_buffer_ = _CustomWriter(1, original, wrap_buffer, on_write)
        sys.stdout_original = original
        sys.stdout = pydevd_io.IORedirector(original, sys._pydevd_out_buffer_, wrap_buffer)  # @UndefinedVariable

:param wrap_stream:
            Either sys.stdout or sys.stderr.

        :param bool wrap_buffer:
            If True the buffer attribute (which wraps writing bytes) should be
            wrapped.

        :param callable(str) on_write:
            May be a custom callable to be called when to write something.
            If not passed the default implementation will create an io message
            and send it through the debugger.
        '''
        self.encoding = getattr(wrap_stream, 'encoding', os.environ.get('PYTHONIOENCODING', 'utf-8'))
        self._out_ctx = out_ctx
        if wrap_buffer:
            self.buffer = _CustomWriter(out_ctx, wrap_stream, wrap_buffer=False, on_write=on_write)
        self._on_write = on_write