code: def save_file(self, data, dfile):
          
          self.enforce_type(self.jobject, "weka.core.converters.FileSourcedConverter")
          if not javabridge.is_instance_of(dfile, "Ljava/io/File;"):
              dfile = javabridge.make_instance(
                  "Ljava/io/File;", "(Ljava/lang/String;)V", javabridge.get_env().new_string_utf(str(dfile)))
          javabridge.call(self.jobject, "setFile", "(Ljava/io/File;)V", dfile)
          javabridge.call(self.jobject, "setInstances", "(Lweka/core/Instances;)V", data.jobject)
          javabridge.call(self.jobject, "writeBatch", "()V")
docs: Saves the Instances object in the specified file.
  
          :param data: the data to save
          :type data: Instances
          :param dfile: the file to save the data to
          :type dfile: str