code: def delete_branch(self, repo_name, branch_name):
          
          res = proto.DeleteBranchRequest(repo=Repo(name=repo_name), branch=branch_name)
          self.stub.DeleteBranch(res, metadata=self.metadata)
docs: Deletes a branch, but leaves the commits themselves intact. In other
          words, those commits can still be accessed via commit IDs and other
          branches they happen to be on.
  
          Params:
          * repo_name: The name of the repo.
          * branch_name: The name of the branch to delete.