docs: public void setDBSubnetGroups(java.util.Collection<DBSubnetGroup> dBSubnetGroups) {
          if (dBSubnetGroups == null) {
              this.dBSubnetGroups = null;
              return;
          }
  
          this.dBSubnetGroups = new java.util.ArrayList<DBSubnetGroup>(dBSubnetGroups);
      }