docs: public void loadTagMappingFile(String file) {
          if (file != null) {
              File f = new File(file);
              if (!f.exists()) {
                  throw new IllegalArgumentException("tag mapping file parameter points to a file that does not exist");
              }
              if (f.isDirectory()) {
                  throw new IllegalArgumentException("tag mapping file parameter points to a directory, must be a file");
              } else if (!f.canRead()) {
                  throw new IllegalArgumentException(
                          "tag mapping file parameter points to a file we have no read permissions");
              }
  
              try {
                  this.tagMapping = f.toURI().toURL();
              } catch (MalformedURLException e) {
                  throw new RuntimeException(e);
              }
          } else {
              this.tagMapping = PoiWriterTask.class.getClassLoader().getResource("poi-mapping.xml");
          }
      }