-- This module implements {{error}}.  local p = {}  local HtmlBuilder = require('Modul:HtmlBuilder')  local function _error(args)     local message = args.message or args[1] or error('no message specified', 2)     message = tostring(message)     local tag = mw.ustring.lower(tostring(args.tag))      -- Work out what html tag we should use.     if not (tag == 'p' or tag == 'span' or tag == 'div') then         tag = 'strong'     end      -- Generate the html.     local root = HtmlBuilder.create(tag)     root         .addClass('error')         .wikitext(message)      return tostring(root) end  function p.error(frame)     local args     if frame == mw.getCurrentFrame() then         -- We're being called via #invoke. The args are passed through to the module         -- from the template page, so use the args that were passed into the template.         args = frame.args     else         -- We're being called from another module or from the debug console, so assume         -- the args are passed in directly.         args = frame     end     -- if the message parameter is present but blank, change it to nil so that Lua will     -- consider it false.     if args.message == "" then         args.message = nil     end     return _error(args) end  return p