class myForm(FlaskForm):
    def __init__(self, *args, **kwargs):
        super(myForm, self).__init__(*args, **kwargs)

@app.route('/search')
def search():
    class F(myForm):
        pass

    fields = {'mytext': wtforms.TextField('myText'),
              'myselect': wtForms.SelectField('mySelect', choices = [(1, 'a'), (2, 'b')])
              }

    for key, val in fields.iteritems():
        setattr(F, key, val)

    form = F()

    return render_template('search.html',
                            form=form)