### Question:
Conversation extends TypedData { static boolean isNullOrBlank(String s) { return s == null || s.trim().length() == 0; } Conversation(); static Conversation find(String id); static Conversation find(String id, Map<String, String> params); static ConversationCollection list(); static ConversationCollection list(Map<String, String> params); static Conversation reply(String id, UserReply reply); static Conversation reply(String id, AdminReply reply); static Conversation markAsRead(String id); static UserMessage create(UserMessage message); static ContactMessage create(ContactMessage message); static AdminMessage create(AdminMessage message); static Conversation runAssignmentRules(String id); String getType(); Admin getCurrentAssignee(); Optional<ConversationPart> getFirstConversationPart(); ConversationPart getMostRecentConversationPart(); String getId(); ConversationMessage getConversationMessage(); CustomerFirstReply getCustomerFirstReply(); ConversationRating getConversationRating(); User getUser(); Admin getAssignee(); long getCreatedAt(); long getUpdatedAt(); long getWaitingSince(); long getSnoozedUntil(); ConversationPartCollection getConversationPartCollection(); TagCollection getTagCollection(); boolean getOpen(); boolean getRead(); String getState(); @Override boolean equals(Object o); @Override int hashCode(); @Override String toString();  }### Answer:
@Test public void testIsNullOrBlank() { assertTrue(Conversation.isNullOrBlank(null)); assertTrue(Conversation.isNullOrBlank("")); assertTrue(Conversation.isNullOrBlank(" ")); assertTrue(Conversation.isNullOrBlank("\n")); assertTrue(Conversation.isNullOrBlank("\r")); assertFalse(Conversation.isNullOrBlank("reply")); }