code: def from_config(cls, cfg, input_shape):
      if isinstance(input_shape, (list, tuple)):
          input_shape = input_shape[0]
      return {"in_channels": input_shape.channels}
  
file_path: PaddleDetection/ppdet/modeling/reid/fairmot_embedding_head.py
imports: import numpy
  import math
  import paddle
  import paddle.nn
  import paddle.nn.functional
  from paddle.nn.initializer import KaimingUniform, Uniform
  from ppdet.core.workspace import register
  from ppdet.modeling.heads.centernet_head import ConvLayer
label_desc: Use image node_id 2 for calling the FairMOTEmbeddingHead obj's underlying member method code with example usage: obj.from_config(cls, cfg, input_shape) and returns: dict