`THROW` ignores all args except the first.

[python-processing-unit]

According to the specification section 9.1.8:

THROW() or THROW(INT|STR: a1, ..., INT|STR: aN) = MUST raise a runtime error. When one or more arguments are supplied, the error message MUST be formed by concatenating those arguments using the same rendering rules as PRINT, but without a trailing newline.

In the implementation, however, THROW only inspects args[0], and only if it is a STR. If args[0] is a string, it is thrown; otherwise the fixed message "Exception thrown" is used. All other arguments, including non-string types and subsequent strings, are silently ignored and not concatenated.