code: def flatatt(self, **attr):
          '''Return a string with attributes to add to the tag'''
          cs = ''
          attr = self._attr
          classes = self._classes
          data = self._data
          css = self._css
          attr = attr.copy() if attr else {}
          if classes:
              cs = ' '.join(classes)
              attr['class'] = cs
          if css:
              attr['style'] = ' '.join(('%s:%s;' % (k, v) for
                                        k, v in css.items()))
          if data:
              for k, v in data.items():
                  attr['data-%s' % k] = dump_data_value(v)
          if attr:
              return ''.join(attr_iter(attr))
          else:
              return 'f flatatt(self, **attr):
          '''Return a string with attributes to add to the tag'''
          cs = ''
          attr = self._attr
          classes = self._classes
          data = self._data
          css = self._css
          attr = attr.copy() if attr else {}
          if classes:
              cs = ' '.join(classes)
              attr['class'] = cs
          if css:
              attr['style'] = ' '.join(('%s:%s;' % (k, v) for
                                        k, v in css.items()))
          if data:
              for k, v in data.items():
                  attr['data-%s' % k] = dump_data_value(v)
          if attr:
              return ''.join(attr_iter(attr))
          else:
              return ''
docs: Return a string with attributes to add to the tag