docs: def create_branch(self, branch_name):
          """
          Create a new branch based on the working tree's revision.
  
          :param branch_name: The name of the branch to create (a string).
  
          This method automatically checks out the new branch, but note that the
          new branch may not actually exist until a commit has been made on the
          branch.
          """
          # Make sure the local repository exists and supports a working tree.
          self.create()
          self.ensure_working_tree()
          # Create the new branch in the local repository.
          logger.info("Creating branch '%s' in %s ..", branch_name, format_path(self.local))
          self.context.execute(*self.get_create_branch_command(branch_name))