Tanks game script SetHealthUI error

 using UnityEngine;
 using UnityEngine.UI;
 
 public class TankHealth : MonoBehaviour
 {
     public float m_StartingHealth = 100f;               // The amount of health each tank starts with.
     public Slider m_Slider;                             // The slider to represent how much health the tank currently has.
     public Image m_FillImage;                           // The image component of the slider.
     public Color m_FullHealthColor = Color.green;       // The color the health bar will be when on full health.
     public Color m_ZeroHealthColor = Color.red;         // The color the health bar will be when on no health.
     public GameObject m_ExplosionPrefab;                // A prefab that will be instantiated in Awake, then used whenever the tank dies.
     
     
     private AudioSource m_ExplosionAudio;               // The audio source to play when the tank explodes.
     private ParticleSystem m_ExplosionParticles;        // The particle system the will play when the tank is destroyed.
     private float m_CurrentHealth;                      // How much health the tank currently has.
     private bool m_Dead;                                // Has the tank been reduced beyond zero health yet?
     
     
     private void Awake ()
     {
         // Instantiate the explosion prefab and get a reference to the particle system on it.
         m_ExplosionParticles = Instantiate (m_ExplosionPrefab).GetComponent<ParticleSystem> ();
         
         // Get a reference to the audio source on the instantiated prefab.
         m_ExplosionAudio = m_ExplosionParticles.GetComponent<AudioSource> ();
         
         // Disable the prefab so it can be activated when it's required.
         m_ExplosionParticles.gameObject.SetActive (false);
     }
     
     
     private void OnEnable()
     {
         // When the tank is enabled, reset the tank's health and whether or not it's dead.
         m_CurrentHealth = m_StartingHealth;
         m_Dead = false;
         
         // Update the health slider's value and color.
         SetHealthUI();
     }
     
     
     public void TakeDamage (float amount)
     {
         // Reduce current health by the amount of damage done.
         m_CurrentHealth -= amount;
         
         // Change the UI elements appropriately.
         SetHealthUI ();
         
         // If the current health is at or below zero and it has not yet been registered, call OnDeath.
         if (m_CurrentHealth <= 0f && !m_Dead)
         {
             OnDeath ();
         }
     }
     
     
     private void SetHealthUI ()
     {
         // Set the slider's value appropriately.
         m_Slider.value = m_CurrentHealth;
         
         // Interpolate the color of the bar between the choosen colours based on the current percentage of the starting health.
         m_FillImage.color = Color.Lerp (m_ZeroHealthColor, m_FullHealthColor, m_CurrentHealth / m_StartingHealth);
     }
     
     
     private void OnDeath ()
     {
         // Set the flag so that this function is only called once.
         m_Dead = true;
         
         // Move the instantiated explosion prefab to the tank's position and turn it on.
         m_ExplosionParticles.transform.position = transform.position;
         m_ExplosionParticles.gameObject.SetActive (true);
         
         // Play the particle system of the tank exploding.
         m_ExplosionParticles.Play ();
         
         // Play the tank explosion sound effect.
         m_ExplosionAudio.Play();
         
         // Turn the tank off.
         gameObject.SetActive (false);
     }
 }`101010`