docs: def icon(self):
          """
          Returns the icon filepath for this plugin.
          
          :return     <str>
          """
          path = self._icon
          if not path:
              return ''
  
          path = os.path.expandvars(os.path.expanduser(path))
          if path.startswith('.'):
              base_path = os.path.dirname(self.filepath())
              path = os.path.abspath(os.path.join(base_path, path))
  
          return path