code: public void removeOverride(String operation) {
          if (this.overrideOnce.containsKey(operation) == true) {
              this.overrideOnce.remove(operation);
          }
  
          if (this.override.containsKey(operation) == true) {
              this.override.remove(operation);
          }
      }
docs: Removes override.
  
  @param operation name of the operation