Session07

Whenever possible and practical it's best to minimize the number of units (classes, methods, and functions) being used in a unit test. This test requires three methods of the `Element()` class to be functioning correctly for it to pass. It's testing that the `__init__()` method accepts a string input, that `.append()` will accept a string or a class, and that `.render()` will write the various tags, strings, and indentation in the desired manner. If this test fails you'll need to look for the failure in multiple units; if a more tightly scoped test fails you'll know exactly where the problem is.