code: def get_framework(cls, properties=None):
          # type: (Optional[dict]) -> Framework
          
          if cls.__singleton is None:
              # Normalize sys.path
              normalize_path()
              cls.__singleton = Framework(properties)
  
          return cls.__singleton
docs: If it doesn't exist yet, creates a framework with the given properties,
          else returns the current framework instance.
  
          :return: A Pelix instance