There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "To specify the position within the grid, the row, and column keywords are used."

A block of code is set as follows:

self.label_text = tk.StringVar()
self.label_text.set("Choose One")

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

def say_hello(self):
    message = "Hello there " + self.name_entry.get()
    msgbox.showinfo("Hello", message)

Any command-line input or output is written as follows:

>>> import tkinter
>>> tkinter.TkVersion

Bold: Indicates a new term, an important word, or words that you see onscreen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "The last thing to do is to create the method that will be responsible for placing it into our Tools menu."