AlliedModders - Undefined Symbol Error

I searched on here and on google and I couldn't find a fix that worked for me so I'm posting this here. I'm going through the tutorial for getting started with plugins and I'm getting the following error

/home/groups/sourcemod/upload_tmp/phpiJRzEt.sp(43) : error 017: undefined symbol "SlapPlayer"

I'm not sure what is causing this and I've tried reinstalling SM and using the online Compiler. Did the command for this change? Did I make a stupid mistake? Any help would be much appreciated. Also if I have the wrong sub forum let me know and I will gladly move this to wherever this does belong.

#include <sourcemod>

new Handle:sm_myslap_damage = INVALID_HANDLE

public Plugin:myinfo =
{
name = "My First Plugin",
author = "Me",
description = "My first plugin ever",
version = "1.0.0.0"
}

public OnPluginStart()
{
RegAdminCmd("sm_myslap", Command_MySlap, ADMFLAG_SLAY)

sm_myslap_damage = CreateConVar("sm_myslap_damage", "5", "Default slap damage")
AutoExecConfig(true, "plugin_myslap")
}

public Action:Command_MySlap(client, args)
{
new String:arg1[32], String:arg2[32]
new damage = GetConVarInt(sm_myslap_damage)

// get the first arg
GetCmdArg(1,arg1,sizeof(arg1))

//if there are 2 or more args and second fetch is successful convert to int
if (args >= 2 && GetCmdArg(2, arg2, sizeof(arg2)))
{
damage = StringToInt(arg2)
}

//try and find a matching player
new target = FindTarget(client, arg1)
if (target == -1)
{
//auto replies with fail reason
return Plugin_Handled;
}

SlapPlayer(target, damage)

new String:name[MAX_NAME_LENGTH]

ShowActivity2(client, "[SM] ", "Slapped %s for %d damage!", name, damage)
LogAction(client, target, "\"%L\" slapped \"%L\" (damage %d)", client, target, damage)

return Plugin_Handled;
}