code: public void setValidUpgradeTarget(java.util.Collection<UpgradeTarget> validUpgradeTarget) {
          if (validUpgradeTarget == null) {
              this.validUpgradeTarget = null;
              return;
          }
  
          this.validUpgradeTarget = new java.util.ArrayList<UpgradeTarget>(validUpgradeTarget);
      }
docs: <p>
  A list of engine versions that this database engine version can be upgraded to.
  </p>
  
  @param validUpgradeTarget
  A list of engine versions that this database engine version can be upgraded to.