class_docstr: Creates a very simple dropdown listing choices from which entries can be selected.
  Preprocessing: Preprocessing: passes the value of the selected dropdown entry as a {str}.
  Postprocessing: expects a {str} corresponding to the value of the dropdown entry to be selected.
  Examples-format: a {str} representing the drop down value to select.
  Demos: sentence_builder, titanic_survival
code: def postprocess(self, y):
      if y is None:
          return None
      self._warn_if_invalid_choice(y)
      return y
  
file_path: gradio/gradio/_simple_templates/simpledropdown.py
imports: from __future__ import annotations
  import warnings
  from typing import Any, Callable
  from gradio.components.base import FormComponent
  from gradio.events import Events
label_desc: Use image node_id 6 for calling the SimpleDropdown obj's underlying member method code with example usage: obj.postprocess(y) and returns: y, None