Python：gettext（）问题

Question

我正在使用flask_babelex模块翻译项目中的字符串。以下给出的方案是英语到日语翻译：

这是实际的字符串：

     gettext(
         'The font size to use for the SQL text boxes and editors. '
         'The value specified is in "em" units, in which 1 is the  '
         'default relative font size. For example, to increase the '
         'font size by 20 percent use a value of 1.2, or to reduce '
         'by 20 percent, use a value of 0.8. Minimum 0.1, maximum 10.'
     )

它失败了：

../venv/lib/python3.6/site-packages/flask_babelex/\__init__.py +534

出现以下错误：

  File "/Users/admin/Documents/projects/venv/lib/python3.6/site-packages/flask_babelex/__init__.py", line 623, in gettext
    return get_domain().gettext(*args, **kwargs)
  File "/Users/admin/Documents/projects/venv/lib/python3.6/site-packages/flask_babelex/__init__.py", line 534, in gettext
    return t.ugettext(string) % variables

ValueError: unsupported format character '?' (0x5927) at index 70

当我使用pyCharm调试问题时，它会在调试窗口中显示。

我无法弄清楚这里有什么问题？