   }
   
   func testOptionalBool() {
-    let key = "boolKey"
+    let key = UUID().uuidString
     XCTAssertTrue(!userDefaults.hasKey(key))
     
     userDefaults.set(true, forKey: key)

  }

  func testRemoveAll() {
    let key = "intKey"
    XCTAssertTrue(!userDefaults.hasKey(key))
    
    userDefaults.set(10, forKey: key)
    XCTAssertNotNil(userDefaults.value(forKey: key))
    
    let key2 = "doubleKey"
    XCTAssertTrue(!userDefaults.hasKey(key2))
    
    userDefaults.set(Double(10), forKey: key2)
    XCTAssertNotNil(userDefaults.value(forKey: key2))
    
    let key3 = "doubleKey"
    XCTAssertTrue(userDefaults.hasKey(key3))
    
    userDefaults.set(10.0, forKey: key3)
    XCTAssertNotNil(userDefaults.value(forKey: key3))

  }

  func testOptionalInt() {
    let key = UUID().uuidString
    XCTAssertTrue(!userDefaults.hasKey(key))
    
    userDefaults.set(10, forKey: key)
