There appears to be some issues with multi-line expressions in Win 10 and 2.3.13 a simple expression like this gives an error but will work sometimes after ignoring the error warning. Error happens in Ubuntu Studio as well.
I just tested it on Linux Ubuntu Studio 10 and I get the same error. The code works fine just gives the error when you click okay after inputting the expression.
This expression is incorrect. Multi-line expressions look like this:
if frame < 150:
ret = frame * 10
else:
ret = 150 * 10
See the tooltip for the “Multi-line” button:
"When checked the Python expression will be interpreted as series of statement. The return value should be then assigned to the ret variable. When unchecked the expression must not contain any new line character and the result will be interpreted from the interpretation of the single line.