code: def brancher(  # noqa: E302
      self, branches=None, all_branches=False, tags=None, all_tags=False
  ):
      
      if not any([branches, all_branches, tags, all_tags]):
          yield ""
          return
  
      saved_tree = self.tree
      revs = []
  
      scm = self.scm
  
      if self.scm.is_dirty():
          from dvc.scm.tree import WorkingTree
  
          self.tree = WorkingTree(self.root_dir)
          yield "Working Tree"
  
      if all_branches:
          branches = scm.list_branches()
  
      if all_tags:
          tags = scm.list_tags()
  
      if branches is None:
          revs.extend([scm.active_branch()])
      else:
          revs.extend(branches)
  
      if tags is not None:
          revs.extend(tags)
  
      # NOTE: it might be a good idea to wrap this loop in try/finally block
      # to don't leave the tree on some unexpected branch after the
      # `brancher()`, but this could cause problems on exception handling
      # code which might expect the tree on which exception was raised to
      # stay in place. This behavior is a subject to change.
      for rev in revs:
          self.tree = scm.get_tree(rev)
          yield rev
  
      self.tree = saved_tree
docs: Generator that iterates over specified revisions.
  
      Args:
          branches (list): a list of branches to iterate over.
          all_branches (bool): iterate over all available branches.
          tags (list): a list of tags to iterate over.
          all_tags (bool): iterate over all available tags.
  
      Yields:
          str: the display name for the currently selected tree, it could be:
              - a git revision identifier
              - empty string it there is no branches to iterate over
              - "Working Tree" if there are uncommited changes in the SCM repo