package org.exoplatform.calendar.model;
<BUG>import java.util.ArrayList;</BUG>
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
<BUG>import java.util.Set;
import org.exoplatform.calendar.model.AbstractModel;</BUG>
import org.exoplatform.calendar.service.Attachment;

package org.exoplatform.calendar.model;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import org.exoplatform.calendar.service.Attachment;
