void InferOpAttributes(
    const OpDef& op_def,
    std::unordered_map<string, string>* inferred_input_attrs);

bool ArgIsList(const OpDef::ArgDef& arg);

bool HasOptionalAttrs(
    const ApiDef& api_def,
    const std::unordered_map<string, string>& inferred_input_attrs);

struct OpInfo {
  // graph_op_def: The OpDef used by the runtime, has the names that