code: public Handshake withParties(HandshakeParty... parties) {
          if (this.parties == null) {
              setParties(new java.util.ArrayList<HandshakeParty>(parties.length));
          }
          for (HandshakeParty ele : parties) {
              this.parties.add(ele);
          }
          return this;
      }
docs: <p>
  Information about the two accounts that are participating in the handshake.
  </p>
  <p>
  <b>NOTE:</b> This method appends the values to the existing list (if any). Use
  {@link #setParties(java.util.Collection)} or {@link #withParties(java.util.Collection)} if you want to override
  the existing values.
  </p>
  
  @param parties
  Information about the two accounts that are participating in the handshake.
  @return Returns a reference to this object so that method calls can be chained together.