code: def set_asset_dir(self):
          
          log = logging.getLogger(self.cls_logger + '.get_asset_dir')
          try:
              self.asset_dir = os.environ['ASSET_DIR']
          except KeyError:
              log.warn('Environment variable ASSET_DIR is not set!')
          else:
              log.info('Found environment variable ASSET_DIR: {a}'.format(a=self.asset_dir))
docs: Returns the ASSET_DIR environment variable
  
          This method gets the ASSET_DIR environment variable for the
          current asset install. It returns either the string value if
          set or None if it is not set.
  
          :return: None