getPersistentData() stops compiling

entity.getPersistentData().putDouble("redrep", (entity.getPersistentData().getDouble("redrep") - 1));
^
symbol: method getPersistentData()
location: variable entity of type Entity
3 errors
> Task :compileJava FAILED

This is one of the three errors my console showed me. What I did was create a procedure for when my custom mob dies (Im creating a faction reputation system and this is a guard for a faction) so when this mob dies it sets the event entities custom number nbt tag "redrep" (reputation of the red faction) to the current redrep subtracted by 1. however this block code is stopping my stuff from compiling somehow and I cant figure out what it is or how to fix it myself.