Conventions

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "Notice that in my test, I instantiate a NumberGuesser object."

A block of code is set as follows:

def given_no_information_when_asked_to_guess_test():
  number_guesser = NumberGuesser()
  result = number_guesser.guess()
  assert result is None, "Then it should provide no result."

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

      for the_class, trained_observations in self._classifications.items():
 if len(trained_observations) <= 1:

 return None
        probability_of_observation_given_class[the_class] = self._probability_given_class(trained_observations, observation)
 [default]
 

Note

Warnings or important notes appear in a box like this.

Tip

Tips and tricks appear like this.