 
 class PythonRuntimeTests: XCTestCase {
 
-  override func setUp() {
+  override class func setUp() {
     super.setUp()
-    PythonLibrary.useVersion(2, 7)
+    PythonLibrary.useVersion(3, 7)
   }
 
   func testCheckVersion() {
-    XCTAssertEqual("2.7.", String(Python.version)!.prefix(4))
+    XCTAssertEqual("3.7.", String(Python.version)!.prefix(4))
     let versionInfo = Python.versionInfo
-    XCTAssertEqual(2, versionInfo.major)
+    XCTAssertEqual(3, versionInfo.major)
     XCTAssertEqual(7, versionInfo.minor)
   }
 

    XCTAssertEqual("[0, 1, 2]", list.description)
    XCTAssertEqual(3, Python.len(list))
    XCTAssertEqual("[0, 1, 2]", Python.str(list))
    XCTAssertEqual("<type 'list'>", Python.str(Python.type(list)))

    let polymorphicList = PythonObject(["a", 2, true, 1.5])
    XCTAssertEqual("a", polymorphicList[0])

    XCTAssertEqual([-1, 0, 0, 1, 10], array.sorted())
    let list: PythonObject = [-1, 10, 1, 0, 0]
    XCTAssertEqual([-1, 0, 0, 1, 10], list.sorted())
  }

  func testHashable() {
