How to use the tableaudocumentapi.Datasource.from_file function in tableaudocumentapi

def test_can_extract_connection(self):
        ds = Datasource.from_file(self.tds_file.name)
        self.assertIsInstance(ds.connections[0], Connection)
        self.assertIsInstance(ds.connections, list)

def test_can_open_tdsx(self):
        ds = Datasource.from_file(self.tdsx_file.name)
        self.assertTrue(ds.connections)
        self.assertTrue(ds.name)

def test_exception_when_datasource_given_twbx(self):
        with self.assertRaises(TableauInvalidFileException):
            ds = Datasource.from_file(TABLEAU_10_TWBX)

def test_can_save_tds(self):
        original_tds = Datasource.from_file(self.tds_file.name)
        original_tds.connections[0].dbname = 'newdb'
        original_tds.save()

        new_tds = Datasource.from_file(self.tds_file.name)
        self.assertEqual(new_tds.connections[0].dbname, 'newdb')

def test_can_extract_datasource_from_file(self):
        ds = Datasource.from_file(self.tds_file.name)
        self.assertEqual(ds.name, 'sqlserver.17u3bqc16tjtxn14e2hxh19tyvpo')
        self.assertEqual(ds.version, '9.3')

def test_can_open_tdsx_and_save_as_changes(self):
        new_tdsx_filename = 'newtdsx.tdsx'
        original_wb = Datasource.from_file(self.tdsx_file.name)
        original_wb.connections[0].server = 'newdb'
        original_wb.save_as(new_tdsx_filename)

        new_wb = Datasource.from_file(new_tdsx_filename)
        self.assertEqual(new_wb.connections[
                         0].server, 'newdb')
        os.unlink(new_tdsx_filename)

def test_can_open_tdsx_and_save_changes(self):
        original_tdsx = Datasource.from_file(self.tdsx_file.name)
        original_tdsx.connections[0].server = 'newdb'
        original_tdsx.save()

        new_tdsx = Datasource.from_file(self.tdsx_file.name)
        self.assertEqual(new_tdsx.connections[
                         0].server, 'newdb')

def test_datasource_can_remove_caption(self):
        filename = self.get_temp_file('test_datasource_can_remove_caption')
        del self.ds.caption
        self.ds.save_as(filename)

        actual = Datasource.from_file(filename)
        self.assertIsNotNone(actual)
        self.assertEqual(actual.caption, '')