code: def symbolic(g, input, target, gamma, alpha, weight, reduction):
      return g.op(
          "mmcv::MMCVSigmoidFocalLoss",
          input,
          target,
          gamma_f=gamma,
          alpha_f=alpha,
          weight_f=weight,
          reduction_s=reduction,
      )
  
imports: import torch
  import torch.nn
  from torch.autograd import Function
  from torch.autograd.function import once_differentiable
  from ..utils import ext_loader
label_desc: Use image node_id 1 for calling the SigmoidFocalLossFunction obj's underlying member method code with example usage: obj.symbolic(g, input, target, gamma, alpha, weight, reduction) and returns: g