code: def __init__(
      self,
      field: str,
      ext_length: int = 0,
      target_field: str = FieldName.TARGET,
  ) -> None:
      self.field = field
      self.ext_length = ext_length
      self.target_field = target_field
  
file_path: gluonts/src/gluonts/mx/model/tft/_transform.py
imports: import numpy
  from gluonts.core.component import validated
  from gluonts.dataset.common import DataEntry
  from gluonts.dataset.field_names import FieldName
  from gluonts.transform import MapTransformation, target_transformation_length
label_desc: Use image node_id 1 to create a new BroadcastTo object from inherited base classes: MapTransformation with example: obj = BroadcastTo(field, ext_length, target_field)