code: def list_branch(self, repo_name):
          
          req = proto.ListBranchRequest(repo=proto.Repo(name=repo_name))
          res = self.stub.ListBranch(req, metadata=self.metadata)
          if hasattr(res, 'branch_info'):
              return res.branch_info
          return []
docs: Lists the active Branch objects on a Repo.
  
          Params:
          * repo_name: The name of the repo.