[impossible_cc]

I have this code, but it doesn't work... I have no idea why. Is something wrong with me?

PHP Code:

public void OnClientPutInServer(int client) 
{ 
    SDKHook(client, SDKHook_OnTakeDamage, Hook_OnTakeDamage);
}
public Action Hook_OnTakeDamage(int victim, int& attacker, int& inflictor, float& damage, int& damagetype) 
{
    if(ValidPlayer(victim) && ValidPlayer(attacker))
    {
        if(GetClientTeam(attacker) == GetClientTeam(victim))
        {
            int heal = 20;
            int oldhp = GetClientHealth(victim);
            
            if(oldhp + heal > 100)
            {
                SetEntityHealth(victim,100);
            }
            else
            {
                SetEntityHealth(victim, heal + oldhp);
            }
            
            PrintToChat(attacker, "You healed your teammate!");
            PrintToChat(victim, "Your teammate healed you!");
        }
    }
    return Plugin_Continue;
}