code: protected Path createTrashLocation(FileSystem fs, Properties props, String user) throws IOException {
      Path trashLocation;
      if (props.containsKey(TRASH_LOCATION_KEY)) {
        trashLocation = new Path(props.getProperty(TRASH_LOCATION_KEY).replaceAll("\\$USER", user));
      } else {
        trashLocation = new Path(fs.getHomeDirectory(), DEFAULT_TRASH_DIRECTORY);
        LOG.info("Using default trash location at " + trashLocation);
      }
      if (!trashLocation.isAbsolute()) {
        throw new IllegalArgumentException("Trash location must be absolute. Found " + trashLocation.toString());
      }
      Path qualifiedTrashLocation = fs.makeQualified(trashLocation);
      ensureTrashLocationExists(fs, qualifiedTrashLocation);
      return qualifiedTrashLocation;
    }
docs: Create location of Trash directory. Parsed from props at key {@link #TRASH_LOCATION_KEY}, defaulting to
  /home/directory/_GOBBLIN_TRASH.
  @param fs {@link org.apache.hadoop.fs.FileSystem} where trash should be found.
  @param props {@link java.util.Properties} containing trash configuration.
  @param user If the trash location contains the token $USER, the token will be replaced by the value of user.
  @return {@link org.apache.hadoop.fs.Path} for trash directory.
  @throws java.io.IOException