code: def add(self, steamid_or_accountname_or_email):
          
          m = MsgProto(EMsg.ClientAddFriend)
  
          if isinstance(steamid_or_accountname_or_email, (intBase, int)):
              m.body.steamid_to_add = steamid_or_accountname_or_email
          elif isinstance(steamid_or_accountname_or_email, SteamUser):
              m.body.steamid_to_add = steamid_or_accountname_or_email.steam_id
          else:
              m.body.accountname_or_email_to_add = steamid_or_accountname_or_email
  
          self._steam.send_job(m)
docs: Add/Accept a steam user to be your friend.
          When someone sends you an invite, use this method to accept it.
  
          :param steamid_or_accountname_or_email: steamid, account name, or email
          :type steamid_or_accountname_or_email: :class:`int`, :class:`.SteamID`, :class:`.SteamUser`, :class:`str`
  
          .. note::
              Adding by email doesn't not work. It's only mentioned for the sake of completeness.