PYTHON IDENTIFIERS

A Python identifier is the name of a variable, function, class, module, or other Python object, and a valid identifier conforms to the following rules:

• It starts with a letter A to Z, or a to z, or an underscore (_).

• It contains zero or more letters, underscores, and digits (0 to 9).

Note: Python identifiers cannot contain characters such as @, $, and %.

Python is a case-sensitive language, so Abc and abc are different identifiers in Python.

In addition, Python has the following naming convention:

• Class names start with an uppercase letter and all other identifiers with a lowercase letter.

• An initial underscore is used for private identifiers.

• Two initial underscores are used for strongly private identifiers.

A Python identifier with two initial underscore and two trailing underscore characters indicates a language-defined special name.