How to use the pypistats._tabulate function in pypistats

| category |    date    | downloads |
|----------|------------|----------:|
| 2.6      | 2018-08-15 |        51 |
| 2.7      | 2018-08-15 |    63,749 |
| 3.2      | 2018-08-15 |         2 |
| 3.3      | 2018-08-15 |        40 |
| 3.4      | 2018-08-15 |     6,095 |
| 3.5      | 2018-08-15 |    20,358 |
| 3.6      | 2018-08-15 |    35,274 |
| 3.7      | 2018-08-15 |     6,595 |
| 3.8      | 2018-08-15 |         3 |
| null     | 2018-08-15 |     1,019 |
"""

        # Act
        output = pypistats._tabulate(data, format="markdown")

        # Assert
        self.assertEqual(output.strip(), expected_output.strip())

| category |    date    | downloads |
|----------|------------|----------:|
| 2.6      | 2018-08-15 |        51 |
| 2.7      | 2018-08-15 |    63,749 |
| 3.2      | 2018-08-15 |         2 |
| 3.3      | 2018-08-15 |        40 |
| 3.4      | 2018-08-15 |     6,095 |
| 3.5      | 2018-08-15 |    20,358 |
| 3.6      | 2018-08-15 |    35,274 |
| 3.7      | 2018-08-15 |     6,595 |
| 3.8      | 2018-08-15 |         3 |
| null     | 2018-08-15 |     1,019 |
"""

        # Act
        output = pypistats._tabulate(data)

        # Assert
        self.assertEqual(output.strip(), expected_output.strip())

def test_versions_are_strings(self):
        # Arrange
        data = copy.deepcopy(SAMPLE_DATA_VERSION_STRINGS)
        expected_output = """
| category |    date    | downloads |
|----------|------------|----------:|
| 3.1      | 2018-08-15 |        10 |
| 3.10     | 2018-08-15 |         1 |
"""

        # Act
        output = pypistats._tabulate(data, format="markdown")

        # Assert
        self.assertEqual(output.strip(), expected_output.strip())

==========  ============  ===========
     2.6         2018-08-15           51 
     2.7         2018-08-15       63,749 
     3.2         2018-08-15            2 
     3.3         2018-08-15           40 
     3.4         2018-08-15        6,095 
     3.5         2018-08-15       20,358 
     3.6         2018-08-15       35,274 
     3.7         2018-08-15        6,595 
     3.8         2018-08-15            3 
     null        2018-08-15        1,019 
    ==========  ============  ===========
"""  # noqa: W291

        # Act
        output = pypistats._tabulate(data, format="rst")

        # Assert
        self.assertEqual(output.strip(), expected_output.strip())

3.8
            2018-08-15
            3
        
        
            null
            2018-08-15
            1,019
        
    

        """

        # Act
        output = pypistats._tabulate(data, format="html")

        # Assert
        self.assertEqual(output.strip(), expected_output.strip())