Error with /sfcalc calc

[EpicPlayerA10]

When i execute this command "/sfcalc calc" without any item i have this error:

org.bukkit.command.CommandException: Unhandled exception executing command 'sfcalc' in plugin SFCalc vDEV - 20 (git 29ba88c6)
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:47) ~[patched_1.16.5.jar:git-Paper-629]
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:159) ~[patched_1.16.5.jar:git-Paper-629]
        at org.bukkit.craftbukkit.v1_16_R3.CraftServer.dispatchCommand(CraftServer.java:810) ~[patched_1.16.5.jar:git-Paper-629]
        at net.minecraft.server.v1_16_R3.PlayerConnection.handleCommand(PlayerConnection.java:2171) ~[patched_1.16.5.jar:git-Paper-629]
        at net.minecraft.server.v1_16_R3.PlayerConnection.c(PlayerConnection.java:1986) ~[patched_1.16.5.jar:git-Paper-629]
        at net.minecraft.server.v1_16_R3.PlayerConnection.a(PlayerConnection.java:1939) ~[patched_1.16.5.jar:git-Paper-629]
        at net.minecraft.server.v1_16_R3.PacketPlayInChat.a(PacketPlayInChat.java:50) ~[patched_1.16.5.jar:git-Paper-629]
        at net.minecraft.server.v1_16_R3.PacketPlayInChat.a(PacketPlayInChat.java:8) ~[patched_1.16.5.jar:git-Paper-629]
        at net.minecraft.server.v1_16_R3.PlayerConnectionUtils.lambda$ensureMainThread$1(PlayerConnectionUtils.java:35) ~[patched_1.16.5.jar:git-Paper-629]
        at net.minecraft.server.v1_16_R3.TickTask.run(SourceFile:18) ~[patched_1.16.5.jar:git-Paper-629]
        at net.minecraft.server.v1_16_R3.IAsyncTaskHandler.executeTask(IAsyncTaskHandler.java:136) ~[patched_1.16.5.jar:git-Paper-629]
        at net.minecraft.server.v1_16_R3.IAsyncTaskHandlerReentrant.executeTask(SourceFile:23) ~[patched_1.16.5.jar:git-Paper-629]
        at net.minecraft.server.v1_16_R3.IAsyncTaskHandler.executeNext(IAsyncTaskHandler.java:109) ~[patched_1.16.5.jar:git-Paper-629]
        at net.minecraft.server.v1_16_R3.MinecraftServer.bb(MinecraftServer.java:1262) ~[patched_1.16.5.jar:git-Paper-629]
        at net.minecraft.server.v1_16_R3.MinecraftServer.executeNext(MinecraftServer.java:1255) ~[patched_1.16.5.jar:git-Paper-629]
        at net.minecraft.server.v1_16_R3.IAsyncTaskHandler.executeAll(IAsyncTaskHandler.java:95) ~[patched_1.16.5.jar:git-Paper-629]
        at net.minecraft.server.v1_16_R3.MinecraftServer.a(MinecraftServer.java:1391) ~[patched_1.16.5.jar:git-Paper-629]
        at net.minecraft.server.v1_16_R3.MinecraftServer.w(MinecraftServer.java:1126) ~[patched_1.16.5.jar:git-Paper-629]
        at net.minecraft.server.v1_16_R3.MinecraftServer.lambda$a$0(MinecraftServer.java:289) ~[patched_1.16.5.jar:git-Paper-629]
        at java.lang.Thread.run(Thread.java:748) [?:1.8.0_292]
Caused by: java.lang.ArrayIndexOutOfBoundsException: 1
        at io.github.seggan.sfcalc.CalcCommand.onExecute(CalcCommand.java:35) ~[?:?]
        at io.github.seggan.sfcalc.infinitylib.commands.CommandManager.onCommand(CommandManager.java:65) ~[?:?]
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:45) ~[patched_1.16.5.jar:git-Paper-629]
        ... 19 more

and this:

[Seggan]

Fixed in build 21