Thank you for your answer! What I try to do is to use European mechanical standards' constants and variable names as local variables inside Modules. Those names include several subscripts, and some of them include 1-3 commas in the subscript part.
I removed my example variable name from definition to expr part of the Module. The color changed from green to blue, and now it seems to be a global variable, because a value is returned when testing the variable outside the Module. The calculation inside the Module started to work, but I need to use local variables to avoid confusions.
Is it possible to use subscripts in local variable names?
Are the commas allowed in subscripts, when variables are used in Conditionals (If, Which...)?