    # File lib/rbot/botuser.rb, line 762
          def login(user, botusername, pwd=nil)
            ircuser = user.to_irc_user
            n = BotUser.sanitize_username(botusername)
            k = n.to_sym
            raise "No such BotUser #{n}" unless include?(k)
            if @botusers.has_key?(ircuser)
              return true if @botusers[ircuser].username == n
              # TODO
              # @botusers[ircuser].logout(ircuser)
            end
            bu = @allbotusers[k]
            if bu.login(ircuser, pwd)
              @botusers[ircuser] = bu
              return true
            end
            return false
          end