Python Naming Convention > Variable Naming

snake_case

Should be all in lowercase
Not begin with the special characters like e.g. & (ampersand), $ (dollar)
If the name contains multiple words, it should be separated by underscores (_) e.g. json_string
Avoid one-character variables e.g. a, b

class Student
    age = None
    ...

Private Variable

Python does not support privacy directly. This naming convention is used as a weak internal use indicator.

Should follow the above naming conventions
Should use a leading underscore (_) to distinguish between "public" and "private" variables
For more read the official python documentation.

class Student:
    age = None # public variable
    _id = 0 # Private variable