docs: def getavailable(self):
          """Return a list of subtitle downloaders available."""
  
          from importlib import import_module
  
          available = []
  
          for script in self.SCRIPTS:
              if have(script):
                  available.append(script)
  
          for module in self.MODULES:
              try:
                  import_module(module)
                  available.append(module)
              except ImportError:
                  pass
  
          return sorted(available)