Procedure to check for a fluid inside a tank + update to the test filling procedure

Hello, i wish to bring forth a procedure idea that would help a lot with making fluid logistic 
- "get fluid type at [x]  [y]  [z] , in tank n°[]"

It could be used with the already existing - "test filling fluid to block at" and the "fill block at" procedure, if it had a new argument to be able to give it a fluid to fill, instead of having a "set fluid" in the procedure :

Use : 

It would make creator be able to properly check for liquids inside a tank, and thus make it able to make a pipe/tank system that can work with multiple fluids
It would also prevent the misuse of filling a fluid tank before checking what liquid you've removed fro manother tank, meaning a modder that didn't thought of that could have players fill a tank with water, then use a "lava" pipe to fill a lava tank that would only check for "if there is fluid  (in this case water) in the sending tank, and thus transform water into lava for example

We could for example very easily do a pipe system like in the picture, where it would check fill a pipe/tank in front of it with the fluid from the internal pipe/tank fluid, so that if possible, would push it's internal content unto the tank in front of it, effectively moving fluid from one pipe to the other and ultimately into a tank if the types of fluid matches !