How do I fix this WaterBase error?

Hi everyone! Before starting, I know it’s possible that this question was made by another user, but I didn’t found a solution for me, so I’m posting to see if someone could help me to solve this. I’ve started following a 2d platformer course a week ago. I’m not a developer, I’m just learning and using my art to make a game, but everything was going fine until this happened.

I was playing arround with the particles to make a cool respawning effect, and I don’t remember why (I suposse it was because an error that showed) deleted a water script That obviously gave me a big error, so after hours of trying things, figured how to reimport that script. But now I have this error:

Assets/Standard Assets/Effects/ImageEffects/Editor/Water (Pro Only)/WaterBaseEditor.cs(8,13): error CS0246: The type or namespace name WaterBase' could not be found. Are you missing UnityStandardAssets.Water' using directive?

I was very happy with the results, but now I'm stuck here and I'm not able to find a solution (Spent days searching on the internet, but 0 luck) And the waterbase files are on their places, I don't get it.

Can somebody help me please?

Here's the part of the code where the problem is supossed to be:

 using UnityEngine;
 using UnityEditor;
 
 [CustomEditor(typeof(WaterBase))]
 public class WaterBaseEditor : Editor 
 {    
     public GameObject oceanBase;
     private WaterBase waterBase;
     private Material oceanMaterial = null;
     
     private SerializedObject serObj;
     private SerializedProperty sharedMaterial;
     
  
     public SerializedProperty waterQuality;
     public SerializedProperty edgeBlend;    
     
     public void OnEnable () 
     {
         serObj = new SerializedObject (target); 
         sharedMaterial = serObj.FindProperty("sharedMaterial"); 
         waterQuality = serObj.FindProperty("waterQuality");           
         edgeBlend = serObj.FindProperty("edgeBlend");           
     }
     
     public override void OnInspectorGUI () 
     {        
         serObj.Update();    
         
         waterBase = (WaterBase)serObj.targetObject;
         oceanBase = ((WaterBase)serObj.targetObject).gameObject;
         if(!oceanBase) 
               return;
                 
         GUILayout.Label ("This script helps adjusting water material properties", EditorStyles.miniBoldLabel);
                 
         EditorGUILayout.PropertyField(sharedMaterial, new GUIContent("Material"));
         oceanMaterial = (Material)sharedMaterial.objectReferenceValue;
 
         if (!oceanMaterial) {
             sharedMaterial.objectReferenceValue = (Object)WaterEditorUtility.LocateValidWaterMaterial(oceanBase.transform);        
             serObj.ApplyModifiedProperties();
             oceanMaterial = (Material)sharedMaterial.objectReferenceValue;
             if (!oceanMaterial)
                 return;
         }