code: def fix_deplist(deps):
      
      deps = [
          ((dep.lower(),)
           if not isinstance(dep, (list, tuple))
           else tuple([dep_entry.lower()
                       for dep_entry in dep
                      ]))
          for dep in deps
      ]
      return deps
docs: Turn a dependency list into lowercase, and make sure all entries
          that are just a string become a tuple of strings