code: def imageSchema(self):
          
  
          if self._imageSchema is None:
              ctx = SparkContext._active_spark_context
              jschema = ctx._jvm.org.apache.spark.ml.image.ImageSchema.imageSchema()
              self._imageSchema = _parse_datatype_json_string(jschema.json())
          return self._imageSchema
docs: Returns the image schema.
  
          :return: a :class:`StructType` with a single column of images
                 named "image" (nullable) and having the same type returned by :meth:`columnSchema`.
  
          .. versionadded:: 2.3.0