class_docstr: Used this instead of torch.nn.Sequential to automate model tracing
class_docstr_tok: ["Used","this","instead","of","torch.nn.Sequential","to","automate","model","tracing"]
code: def input_prototype(self):
      first = self[0]
      assert isinstance(
          first, ModelBase
      ), "The first module of Sequential has to be ModelBase"
      return first.input_prototype()
  
imports: import torch.nn
  from reagent.models.base import ModelBase
label_desc: Use image node_id 1 for calling the Sequential obj's underlying member method code with example usage: obj.input_prototype() and returns: first