What Do Square Brackets in Function and Class Documentation Indicate?

Understanding Square Bracket Usage in Function and Class Documentation

The square brackets, "[ ]", found within function or class documentation denote optional arguments. These arguments are not mandatory for the correct operation of the function or class.

In the provided documentation for csv.DictReader:

class csv.DictReader(csvfile[, fieldnames=None[, restkey=None[, restval=None[, dialect='excel'[, *args, **kwds]]]]])

The csvfile argument is the only mandatory argument, while all subsequent arguments are optional and can be omitted without affecting the functionality of csv.DictReader.

For example, if you only wish to specify the csvfile and dialect arguments, you would need to explicitly name the arguments as follows:

csv.DictReader(file('test.csv'), dialect='excel_tab')

The square brackets serve as a visual cue to indicate that the arguments are optional. By understanding this convention, you can correctly interpret function and class documentation and effectively utilize the available optional arguments.

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