class_docstr: A loss appropriate for regression tasks.
class_docstr_tok: ["A","loss","appropriate","for","regression","tasks","."]
code: def mean_func(self, y_pred):
      return y_pred
  
imports: from __future__ import annotations
  import math
  import numpy
  from scipy import special
  from river import base, utils
  from river.optim.base import Loss
label_desc: Use image node_id 1 for calling the RegressionLoss obj's underlying member method code with example usage: obj.mean_func(y_pred) and returns: y_pred