code: def find_formatter_class(alias):
      
      for module_name, name, aliases, _, _ in itervalues(FORMATTERS):
          if alias in aliases:
              if name not in _formatter_cache:
                  _load_formatters(module_name)
              return _formatter_cache[name]
      for _, cls in find_plugin_formatters():
          if alias in cls.aliases:
              return cls
docs: Lookup a formatter by alias.
  
      Returns None if not found.