code: public DBInstance withOptionGroupMemberships(OptionGroupMembership... optionGroupMemberships) {
          if (this.optionGroupMemberships == null) {
              setOptionGroupMemberships(new java.util.ArrayList<OptionGroupMembership>(optionGroupMemberships.length));
          }
          for (OptionGroupMembership ele : optionGroupMemberships) {
              this.optionGroupMemberships.add(ele);
          }
          return this;
      }
docs: <p>
  Provides the list of option group memberships for this DB instance.
  </p>
  <p>
  <b>NOTE:</b> This method appends the values to the existing list (if any). Use
  {@link #setOptionGroupMemberships(java.util.Collection)} or
  {@link #withOptionGroupMemberships(java.util.Collection)} if you want to override the existing values.
  </p>
  
  @param optionGroupMemberships
  Provides the list of option group memberships for this DB instance.
  @return Returns a reference to this object so that method calls can be chained together.