I would like to have access to the list of tests in a TestSuite object.
Currently there are two ways of doing this: I can access the protected attribute `_tests`, or I can iterate over the TestSuite and re-create data that I already have. The former option isn't part of the public API and makes mypy mad, and the latter seems redundant. Could we get a public property or getter for the internal test list (or a more appropriate implementation if necessary)?