class Herb::Errors::UnclosedElementError

def tree_inspect(indent = 0)
  output = +""
  output += %(@ #{error_name} #{location.tree_inspect}\n)
  output += %(├── message: #{message.inspect}\n)
  output += %(└── opening_tag: #{opening_tag ? opening_tag.tree_inspect : "∅"}\n)
  output += %(\n)
  output.gsub(/^/, "    " * indent)
end