def hidden_tag(self, *fields):

        if not fields:
            fields = [f for f in self if _is_hidden(f)]

        rv = [u'<div style="display:none;">']
        for field in fields:
            if isinstance(field, string_types):
                field = getattr(self, field)
            rv.append(text_type(field))
        rv.append(u"</div>")

        return Markup(u"".join(rv))
Wraps hidden fields in a hidden DIV tag, in order to keep XHTML
dataset/ETHPy150Open RoseOu/flasky/venv/lib/python2.7/site-packages/flask_wtf/form.py/Form.hidden_tag