I believe this code is currently incorrect, as it makes references to code outside the "if code" block, where it can not be ensured that code is a string. Moving the code processing into this block avoids this issue.
I experienced a stuck Addon Manager, which was caused by an exception
```
File "/usr/share/freecad/Mod/AddonManager/addonmanager_macro.py", line ..., in fill_details_from_wiki
FreeCAD.Console.PrintWarning(translate("AddonsInstaller", "Unable to clean macro code: ") + code + '\n')
TypeError: can only concatenate str (not "list") to str
```
which is fixed by these changes.
OS: Ubuntu 20.04.1 LTS
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.4.
Build type: Release
Python version: 3.8.2
Qt version: 5.12.5
Coin version: 4.0.0
OCC version: 7.3.0
Locale: English/United States (en_US)
72eb41b24f