code: def backward_kill_word(event):
      """
      Kills the word before point, using "not a letter nor a digit" as a word boundary.
      Usually bound to M-Del or M-Backspace.
      """
      unix_word_rubout(event, WORD=False)
  
imports: from __future__ import unicode_literals
  from prompt_toolkit.enums import IncrementalSearchDirection, SEARCH_BUFFER
  from prompt_toolkit.selection import PasteMode
  from six.moves import range
  import six
  from .completion import generate_completions, display_completions_like_readline
  from prompt_toolkit.document import Document
  from prompt_toolkit.enums import EditingMode
  from prompt_toolkit.key_binding.input_processor import KeyPress
  from prompt_toolkit.keys import Keys
label_desc: Use image node_id 29 for calling a global function with example usage: backward_kill_word(event) without return types