code: def setUp(self) -> None:
      self.l1_loss = MaskedSmoothL1Loss(beta=0)
      self.smooth_l1_loss = MaskedSmoothL1Loss(beta=1)
      self.pred = torch.FloatTensor([0.5, 1, 1.5, 2])
      self.gt = torch.ones_like(self.pred)
      self.mask = torch.FloatTensor([1, 0, 0, 1])
  
imports: from unittest import TestCase
  import torch
  from mmocr.models.common.losses import MaskedSmoothL1Loss
label_desc: Use image node_id 1 for calling the TestMaskedSmoothL1Loss obj's underlying member method code with example usage: obj.setUp() without return types