Simple /tpa plugin (limited within a single world)

Changed my mind about how I want to go about this (decided not to risk attempting to manage separate inventories on one server). Although I left my idea here just in case.

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Hi,
I'd like a simple /tpa plugin. I don't need /tp or anything else. (I'd rather not install Essentials just to get /tpa for one world.)

The only feature I request for this plugin is that you can only send a /tpa request to players in the same world. I have one creative and one survival world, and I only want players in the Creative world to be able to /tpa to players only in the Creative world. (I want it utterly disabled for those in Survival.)

suggested permission nodes:

plugin.tpa: permission to send request
plugin.tpaccept: permission to accept a request

Optionally, if the plugin can mitigate /tpa spam (sending multiple /tpa requests to multiple players quickly), that'd be nice.