class_docstr: Root mean square error
  
  Defined as ``(y_pred - target)**2``
class_docstr_tok: ["Root","mean","square","error","Defined","as","``","(","y_pred","-","target",")","*","*","2","``"]
code: def __init__(self, reduction="sqrt-mean", **kwargs):
      super().__init__(reduction=reduction, **kwargs)
  
imports: from typing import Any, Callable, Dict, List, Optional, Tuple, Union
  import scipy.stats
  import torch
  import torch.nn.functional
  from torch.nn.utils import rnn
  from pytorch_forecasting.metrics.base_metrics import MultiHorizonMetric
  from pytorch_forecasting.utils import create_mask, unpack_sequence, unsqueeze_like
label_desc: Use image node_id 1 to create a new RMSE object from inherited base classes: MultiHorizonMetric with example: obj = RMSE(reduction)