code: def _is_control(char):
      """Checks whether `chars` is a control character."""
      # These are technically control characters but we count them as whitespace
      # characters.
      if char == "\t" or char == "\n" or char == "\r":
          return False
      cat = unicodedata.category(char)
      if cat in ("Cc", "Cf"):
          return True
      return False
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import collections
  import re
  import unicodedata
  import six
  import tensorflow
label_desc: Use image node_id 10 for calling a global function with example usage: _is_control(char) and returns: False, False, True