code: def set(self, value: Any) -> None:
      if self.multiple:
          if not isinstance(value, list):
              raise Error(
                  "Option %r is required to be a list of %s"
                  % (self.name, self.type.__name__)
              )
          for item in value:
              if item is not None and not isinstance(item, self.type):
                  raise Error(
                      "Option %r is required to be a list of %s"
                      % (self.name, self.type.__name__)
                  )
      else:
          if value is not None and not isinstance(value, self.type):
              raise Error(
                  "Option %r is required to be a %s (%s given)"
                  % (self.name, self.type.__name__, type(value))
              )
      self._value = value
      if self.callback is not None:
          self.callback(self._value)
  
imports: import datetime
  import numbers
  import re
  import sys
  import os
  import textwrap
  from tornado.escape import _unicode, native_str
  from tornado.log import define_logging_options
  from tornado.util import basestring_type, exec_in
  from typing import Any, Iterator, Iterable, Tuple, Set, Dict, Callable, List, TextIO, Optional
label_desc: Use image node_id 4 for calling the _Option obj's underlying member method code with example usage: obj.set(value) without return types