class_docstr: This class handles the parser event from opt_parser.
  When a target statement is matched, an event is triggered,
  we collected necessary information from this event and construct
  the branches as what we want to understand.
code: def rf_mul_add_resolve(self, op_list):
      branch = Branch()
      branch.batchmatmul = op_list[0]
      branch.outputs = branch.batchmatmul.outputs
      branch.add2 = None
      if len(op_list) == 2:
          branch.add2 = op_list[1]
          branch.outputs = branch.add2.outputs
      return branch
  
imports: import nnabla
label_desc: Use image node_id 9 for calling the OptimizerBuilder obj's underlying member method code with example usage: obj.rf_mul_add_resolve(op_list) and returns: branch