docstr: KeyPointMSELoss layer
  
  Args:
      use_target_weight (bool): whether to use target weight
docstr_tok: ["KeyPointMSELoss","layer","Args",":","use_target_weight","(","bool",")",":","whether","to","use","target","weight"]
code: def __init__(self, use_target_weight=True, loss_scale=0.5):
      """
      KeyPointMSELoss layer
  
      Args:
          use_target_weight (bool): whether to use target weight
      """
      super(KeyPointMSELoss, self).__init__()
      self.criterion = nn.MSELoss(reduction="mean")
      self.use_target_weight = use_target_weight
      self.loss_scale = loss_scale
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from itertools import cycle, islice
  from collections import abc
  import numpy
  import paddle
  import paddle.nn
  from ppdet.core.workspace import register, serializable
label_desc: Use image node_id 1 to create a new KeyPointMSELoss object from inherited base classes: nn with example: obj = KeyPointMSELoss(use_target_weight, loss_scale)