How to use the quandl.model.data.Data.all function in Quandl

def test_to_csv_returns_expected_csv(self):
        results = Data.all(
            params={'database_code': 'NSE', 'dataset_code': 'OIL'})
        data = results.to_csv()
        expected = "Date,column.1,column.2,column.3\n2015-07-11,444.3,10,3\n" + \
                   "2015-07-13,433.3,4,3\n2015-07-14,437.5,3,3\n2015-07-15,440.0,2,3\n"
        self.assertEqual(data, expected)

def test_data_to_list(self):
        list_data = Data.all(
            params={'database_code': 'NSE', 'dataset_code': 'OIL'}).to_list()
        six.assertCountEqual(self, list_data[0], self.expected_list_values[0])
        six.assertCountEqual(self, list_data[1], self.expected_list_values[1])
        six.assertCountEqual(self, list_data[2], self.expected_list_values[2])
        six.assertCountEqual(self, list_data[3], self.expected_list_values[3])

        self.assertRaises(InvalidDataError, lambda: Data.all())

def test_pandas_dataframe_index_is_datetime(self):
        results = Data.all(
            params={'database_code': 'NSE', 'dataset_code': 'OIL'})
        df = results.to_pandas()
        self.assertEqual(df.index.name, 'Date')
        self.assertIsInstance(df.index, pandas.DatetimeIndex)

def test_raw_data_is_zip_of_column_names_and_data(self):
        results = Data.all(
            params={'database_code': 'NSE', 'dataset_code': 'OIL'})
        six.assertCountEqual(self, results[0].__get_raw_data__(), self.expected_list_values[0])
        six.assertCountEqual(self, results[1].__get_raw_data__(), self.expected_list_values[1])
        six.assertCountEqual(self, results[2].__get_raw_data__(), self.expected_list_values[2])
        six.assertCountEqual(self, results[3].__get_raw_data__(), self.expected_list_values[3])

def test_values_and_meta_exist(self):
        results = Data.all(
            params={'database_code': 'NSE', 'dataset_code': 'OIL'})
        self.assertIsNotNone(results.values)
        self.assertIsNotNone(results.meta)

def test_data_calls_connection(self, mock):
        Data.all(params={'database_code': 'NSE', 'dataset_code': 'OIL'})
        expected = call('get', 'datasets/NSE/OIL/data', params={})
        self.assertEqual(mock.call_args, expected)