def get_cmd(self):
        """Get the cmd to run to build the image"""
        cmd = [
            "jupyter-repo2docker",
        ] + self.get_r2d_cmd_options()

        # repo_url comes at the end, since otherwise our arguments
        # might be mistook for commands to run.
        # see https://github.com/jupyter/repo2docker/pull/128
        cmd.append(self.repo_url)

        return cmd
Get the cmd to run to build the image
binderhub/build.py