code: def getCSS(self):
          
          template = self.request.get('template', self._DEFAULT_TEMPLATE)
          content = ''
          if template.find(':') >= 0:
              prefix, template = template.split(':')
              resource = queryResourceDirectory(
                  self._TEMPLATES_ADDON_DIR, prefix)
              css = '{0}.css'.format(template[:-3])
              if css in resource.listDirectory():
                  content = resource.readFile(css)
          else:
              this_dir = os.path.dirname(os.path.abspath(__file__))
              templates_dir = os.path.join(this_dir, self._TEMPLATES_DIR)
              path = '%s/%s.css' % (templates_dir, template[:-3])
              with open(path, 'r') as content_file:
                  content = content_file.read()
          return content
docs: Returns the css style to be used for the current template.
              If the selected template is 'default.pt', this method will
              return the content from 'default.css'. If no css file found
              for the current template, returns empty string