Argument to_json added to json function in Base view.
Its value (which should be a boolean) determines if the data should be converted to a JSON object. Therefore if someone has already a JSON string and wants to return it in a HTTP response, he or she may set to_json=False and the object will not be converted.
Coverage: code coverage testing for Python
Coverage.py is a Python module that measures code coverage during test execution.
It uses the code analysis tools and tracing hooks provided in the Python standard
library to determine which lines are executable, and which have been executed.
For more information, see http://nedbatchelder.com/code/modules/coverage.html