code: public static Bridge create(final String callId1, final String callId2)
      	    throws Exception {
      	assert (callId1 != null);
      	final BandwidthClient client = BandwidthClient.getInstance();
      	return create(client, callId1, callId2);
  	}
docs: Convenience factory method to create a Bridge object from two call ids
  @param callId1 the call id
  @param callId2 the call id
  @return the Bridge
  @throws IOException unexpected error.