class_docstr: BBox head for `SCNet <https://arxiv.org/abs/2012.10150>`_.
  
  This inherits ``ConvFCBBoxHead`` with modified forward() function, allow us
  to get intermediate shared feature.
docstr: Forward function for shared part.
  
  Args:
      x (Tensor): Input feature.
  
  Returns:
      Tensor: Shared feature.
code: def _forward_shared(self, x: Tensor) -> Tensor:
      """Forward function for shared part.
  
      Args:
          x (Tensor): Input feature.
  
      Returns:
          Tensor: Shared feature.
      """
      if self.num_shared_convs > 0:
          for conv in self.shared_convs:
              x = conv(x)
  
      if self.num_shared_fcs > 0:
          if self.with_avg_pool:
              x = self.avg_pool(x)
  
          x = x.flatten(1)
  
          for fc in self.shared_fcs:
              x = self.relu(fc(x))
  
      return x
  
file_path: mmdetection/mmdet/models/roi_heads/bbox_heads/scnet_bbox_head.py
imports: from typing import Tuple, Union
  from torch import Tensor
  from mmdet.registry import MODELS
  from .convfc_bbox_head import ConvFCBBoxHead
label_desc: Use image node_id 1 for calling the SCNetBBoxHead obj's underlying member method code with example usage: obj._forward_shared(x) and returns: x