How Physics2D.OverlapCircleAll works???

here is my IsGrounded method,,,,

 bool IsGround(){<br>
     if (rigidBody.velocity.y <= 0) {<br>
         foreach(Transform points in groundPoints){<br>
             Collider2D[] colliders = Physics2D.OverlapCircleAll (points.position,0.2f);<br>

             for(int i=0;i<colliders.Length;i++){<br>
                 if (colliders [i].gameObject != gameObject) {<br>
                     return true;<br>
                 }<br>
             }<br>
         }
     }<br>
     return false;<br>
 }

what does this part do?? if (colliders [i].gameObject != gameObject) {
return true;
}