`PRINT` doesn't render `BOOL`.

[python-processing-unit]

According to the specification section 4.0.2:

When a BOOL is converted to STR, TRUE MUST render as TRUE and FALSE MUST render as FALSE.

And the specification section 9.1.12:

BOOL: PRINT(~STR: arg1, ..., ~STR: argN) = MUST convert each argument to STR, concatenate the rendered arguments, append a trailing newline, write the result to the console output, record the corresponding I/O event in the execution log, and return FALSE.

In the implementation, however, PRINT does not render BOOL, falling back to <null> instead.

Prefix REPL. Enter statements, blank line to run buffer.
>>> PRINT(TRUE)
<null>
>>> PRINT(FALSE)
<null>
>>>