kotlin.NotImplementedError

kotlin.NotImplementedError: An operation is not implemented: not implemented
	at de.leonhard.sync.Sync.onPluginStart(Sync.kt:38)
	at de.leonhard.sapphire.spigot.SimplePlugin.onStart(SimplePlugin.java:268)
	at de.leonhard.sapphire.core.Sapphire$Spigot.onEnable(Sapphire.java:316)
	at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:264)
	at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:316)
	at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:405)
	at org.bukkit.craftbukkit.v1_12_R1.CraftServer.enablePlugin(CraftServer.java:395)
	at org.bukkit.craftbukkit.v1_12_R1.CraftServer.enablePlugins(CraftServer.java:344)
	at net.minecraft.server.v1_12_R1.MinecraftServer.t(MinecraftServer.java:442)
	at net.minecraft.server.v1_12_R1.MinecraftServer.l(MinecraftServer.java:403)
	at net.minecraft.server.v1_12_R1.MinecraftServer.a(MinecraftServer.java:341)
	at net.minecraft.server.v1_12_R1.DedicatedServer.init(DedicatedServer.java:289)
	at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:616)
	at java.lang.Thread.run(Thread.java:748)