class_docstr: Graph input tracer using depth-first search.
code: def inputs(self):
      return self._inputs
  
imports: from tensorflow.core.framework import graph_pb2
  from tensorflow.python.framework import op_def_registry
  from tensorflow.python.platform import tf_logging
label_desc: Use image node_id 3 for calling the DFSGraphTracer obj's underlying member method code with example usage: obj.inputs() and returns: self