code: func merge(c1 *fab.ChaincodeCall, c2 *fab.ChaincodeCall) (*fab.ChaincodeCall, bool) {
  	c := &fab.ChaincodeCall{ID: c1.ID, Collections: c1.Collections}
  	merged := false
  	for _, coll := range c2.Collections {
  		if !contains(c.Collections, coll) {
  			c.Collections = append(c.Collections, coll)
  			merged = true
  		}
  	}
  	return c, merged
  }
docs: // merge merges the collections from c1 and c2 and returns the resulting ChaincodeCall.
  // true is returned if a merge was necessary; false is returned if the two ChaincodeCalls were the same.