class_docstr: A `Predictor` that always produces the same value as forecast.
  
  Parameters
  ----------
  value
      The value to use as forecast.
  prediction_length
      Prediction horizon.
code: def __init__(
      self,
      prediction_length: int,
      value: float = 0.0,
      # since we are emitting a constant values, we just predict a single
      # line on default
      num_samples: int = 1,
  ) -> None:
      super().__init__(prediction_length=prediction_length)
      self.value = value
      self.num_samples = num_samples
  
file_path: gluonts/src/gluonts/model/trivial/constant.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.dataset.util import forecast_start
  from gluonts.model.forecast import SampleForecast
  from gluonts.model.predictor import RepresentablePredictor
label_desc: Use image node_id 1 to create a new ConstantValuePredictor object from inherited base classes: RepresentablePredictor with example: obj = ConstantValuePredictor(prediction_length, value, num_samples)