code: public ListInvitationsResult withInvitations(Invitation... invitations) {
          if (this.invitations == null) {
              setInvitations(new java.util.ArrayList<Invitation>(invitations.length));
          }
          for (Invitation ele : invitations) {
              this.invitations.add(ele);
          }
          return this;
      }
docs: <p>
  <b>NOTE:</b> This method appends the values to the existing list (if any). Use
  {@link #setInvitations(java.util.Collection)} or {@link #withInvitations(java.util.Collection)} if you want to
  override the existing values.
  </p>
  
  @param invitations
  @return Returns a reference to this object so that method calls can be chained together.