Valid Identifier Names

A valid identfier is a non-empty sequence of characters of any length with:

• the start character can be the underscore “_” or a capital or lower case letter in Python3: letters from non-English languages, like “Ä”, “ö”, are allowed
• the letters following the start character can be anything which is permitted as a start character plus the digits. in Python3: anything which Unicode considers to be a digit, non-whitespace characters.
• Identifiers are case-sensitive
• Python keywords are not allowed as identifier names