What is internal representation of string in Python 3.x

Question

In Python 3.x, a string consists of items of Unicode ordinal. (See the quotation from the language reference below.) What is the internal representation of Unicode string? I

Answer 1

In Python 3.3 and above, the internal representation of the string will depend on the string, and can be any of latin-1, UCS-2 or UCS-4, as described in PEP 393.

For previous Pythons, the internal representation depends on the build flags of Python. Python can be built with flag values --enable-unicode=ucs2 or --enable-unicode=ucs4. ucs2 builds do in fact use UTF-16 as their internal representation, and ucs4 builds use UCS-4 / UTF-32.