code: def __init__(
      self,
      in_channels,
      norm_type="bn",
      freeze_norm=False,
      norm_decay=0.0,
  ):
      super(IterativeHead, self).__init__()
      num_branches = len(in_channels)
      self.in_channels = in_channels[::-1]
  
      projects = []
      for i in range(num_branches):
          if i != num_branches - 1:
              projects.append(
                  DepthWiseSeparableConvNormLayer(
                      ch_in=self.in_channels[i],
                      ch_out=self.in_channels[i + 1],
                      filter_size=3,
                      stride=1,
                      dw_act=None,
                      pw_act="relu",
                      dw_norm_type=norm_type,
                      pw_norm_type=norm_type,
                      freeze_norm=freeze_norm,
                      norm_decay=norm_decay,
                  )
              )
          else:
              projects.append(
                  DepthWiseSeparableConvNormLayer(
                      ch_in=self.in_channels[i],
                      ch_out=self.in_channels[i],
                      filter_size=3,
                      stride=1,
                      dw_act=None,
                      pw_act="relu",
                      dw_norm_type=norm_type,
                      pw_norm_type=norm_type,
                      freeze_norm=freeze_norm,
                      norm_decay=norm_decay,
                  )
              )
      self.projects = nn.LayerList(projects)
  
imports: import paddle
  import paddle.nn
  import paddle.nn.functional
  from numbers import Integral
  from paddle import ParamAttr
  from paddle.regularizer import L2Decay
  from paddle.nn.initializer import Normal, Constant
  from ppdet.core.workspace import register
  from ppdet.modeling.shape_spec import ShapeSpec
  from ppdet.modeling.ops import channel_shuffle
  from ..None import layers
label_desc: Use image node_id 1 to create a new IterativeHead object from inherited base classes: nn with example: obj = IterativeHead(in_channels, norm_type, freeze_norm, norm_decay)