class_docstr: Runs basic tokenization (punctuation splitting, lower casing, etc.).
docstr: Performs invalid character removal and whitespace cleanup on text.
docstr_tok: ["Performs","invalid","character","removal","and","whitespace","cleanup","on","text","."]
code: def _clean_text(self, text):
      """Performs invalid character removal and whitespace cleanup on text."""
      output = []
      for char in text:
          cp = ord(char)
          if cp == 0 or cp == 0xFFFD or _is_control(char):
              continue
          if _is_whitespace(char):
              output.append(" ")
          else:
              output.append(char)
      return "".join(output)
  
imports: from __future__ import absolute_import, division, print_function
  import collections
  import re
  import unicodedata
  import six
label_desc: Use image node_id 7 for calling the BasicTokenizer obj's underlying member method code with example usage: obj._clean_text(text) and returns: str