code: def branch(self, branch_name, start_point='HEAD', force=True,
                 checkout=False):
          
          return git_branch(
              self.repo_dir, branch_name, start_point, force=force,
              checkout=checkout)
docs: Create branch as in `git branch <branch_name> <start_point>`.
  
          If 'checkout' is True, checkout the branch after creation.