code: def cssify(css_dict):
      
      css = ''
      for key, value in dict_items(css_dict):
          css += '{key} {{ '.format(key=key)
          for field, field_value in dict_items(value):
              css += ' {field}: {field_value};'.format(field=field,
                                                       field_value=field_value)
          css += '} '
      return css.strip()
docs: Function to get CartoCSS from Python dicts