class_docstr: This class defines method to process strings in the most
  efficient way. Ideally all the methods below use unicode strings
  for both input and output.
class_docstr_tok: ["This","class","defines","method","to","process","strings","in","the","most","efficient","way",".","Ideally","all","the","methods","below","use","unicode","strings","for","both","input","and","output","."]
docstr: This function replaces any sequence of non letters and non
  numbers with a single white space.
docstr_tok: ["This","function","replaces","any","sequence","of","non","letters","and","non","numbers","with","a","single","white","space","."]
code: def replace_non_letters_non_numbers_with_whitespace(cls, a_string):
      """
      This function replaces any sequence of non letters and non
      numbers with a single white space.
      """
      return cls.regex.sub(" ", a_string)
  
imports: from __future__ import unicode_literals
  import re
  import string
  import sys
label_desc: Use image node_id 1 for calling the StringProcessor obj's underlying member method code with example usage: obj.replace_non_letters_non_numbers_with_whitespace(cls, a_string) and returns: cls