code: def declare_namespace(packageName):
      
  
      _imp.acquire_lock()
      try:
          if packageName in _namespace_packages:
              return
  
          path = sys.path
          parent, _, _ = packageName.rpartition('.')
  
          if parent:
              declare_namespace(parent)
              if parent not in _namespace_packages:
                  __import__(parent)
              try:
                  path = sys.modules[parent].__path__
              except AttributeError:
                  raise TypeError("Not a package:", parent)
  
          # Track what packages are namespaces, so when new path items are added,
          # they can be updated
          _namespace_packages.setdefault(parent or None, []).append(packageName)
          _namespace_packages.setdefault(packageName, [])
  
          for path_item in path:
              # Ensure all the parent's path items are reflected in the child,
              # if they apply
              _handle_ns(packageName, path_item)
  
      finally:
          _imp.release_lock()
docs: Declare that package 'packageName' is a namespace package