code: def is_string_dunder_all(self, element):
          
          if not isinstance(element.value, (ast.Str, ast.Bytes)):
              return False
  
          node_value = element.value.s
          if isinstance(node_value, bytes):
              node_value = node_value.decode()
          return node_value == '__all__'
docs: Return True if element is ast.Str or ast.Bytes and equals "__all__"