code: def open(self):
      if self.closed is None:
          self.emit(StreamStartEvent(encoding=self.use_encoding))
          self.closed = False
      elif self.closed:
          raise SerializerError("serializer is closed")
      else:
          raise SerializerError("serializer is already opened")
  
file_path: keepsake/python/keepsake/_vendor/yaml/serializer.py
imports: from .error import YAMLError
  from .events import *
  from .nodes import *
label_desc: Use image node_id 2 for calling the Serializer obj's underlying member method code with example usage: obj.open() without return types