Ios swift – "Variable binding in a condition requires initializer" – Firebase iOS SDK producing error

I am trying to use Firebase in my iOS app. I have installed the SDK using cocoapods as incstructed by Firebase’s docs (here)
However, when I build by app I face an error of conditional binding in the source files of firebase as shown in the picture below.

I tried to edit these files and reran the building process. But the problem is that this issue is in hundreds of files and certainly changing each line manually is not the solution.