code: def input_ratio(self, name, choices, labels, multi_line=False):
          
          if len(choices) != len(labels):
              raise ValueError("The size of 'choices' and 'labels' doesn't match!")
          
          choice_label = list(zip(choices, labels))
          
          lines = list()
          lines.append('{%% for value, label in %s %%}' % repr(choice_label))
          lines.append(self.tab + '{%% if %s == value %%}' % name)
          lines.append(self.tab * 2 + '{% set checked = "checked" %}')
          lines.append(self.tab + '{% else %}')
          lines.append(self.tab * 2 + '{% set checked = "" %}')
          lines.append(self.tab + '{% endif %}')
          if multi_line:
              line_break = "<br>"
          else:
              line_break = ""
          lines.append(self.tab + '<input type="radio" name="%s" value="{{value}}" {{checked}} /> {{label}} %s' % (name, line_break))
          lines.append('{% endfor %}')
          return "\n".join(lines)
docs: {% for value, label in [('choice1', '选项1'), ('choice2', '选项2')] %}
              {% if ratio == value %}
                  {% set checked = "checked" %}
              {% else %}
                  {% set checked = "" %}
              {% endif %}
              <input type="radio" name="ratio" value="{{value}}" {{checked}} /> {{label}}
          {% endfor %}