code: def in_channels(m:nn.Module) -> List[int]:
      "Return the shape of the first weight layer in `m`."
      for l in flatten_model(m):
          if hasattr(l, 'weight'): return l.weight.shape[1]
      raise Exception('No weight layer'f in_channels(m:nn.Module) -> List[int]:
      "Return the shape of the first weight layer in `m`."
      for l in flatten_model(m):
          if hasattr(l, 'weight'): return l.weight.shape[1]
      raise Exception('No weight layer')
docs: Return the shape of the first weight layer in `m`.