core/src/main/java/com/orientechnologies/orient/core/command/OBasicCommandContext.java
public synchronized boolean addToUniqueResult(Object o) {
    Object toAdd = o;
    if (o instanceof ODocument && ((ODocument) o).getIdentity().isNew()) {
      toAdd = new ODocumentEqualityWrapper((ODocument) o);
    }
    return this.uniqueResult.add(toAdd);
  }
public synchronized boolean addToUniqueResult(Object o) {
    Object toAdd = o;
    if (o instanceof ODocument && ((ODocument) o).getIdentity().isNew()) {
      toAdd = new ODocumentEqualityWrapper((ODocument) o);
    }
    return this.uniqueResult.add(toAdd);
  }
adds an item to the unique result set

@param o the result item to add

@return true if the element is successfully added (it was not present yet), false otherwise (it was already present)