code: def replace_undesirable_characters(line):
      
      # These are separate because we want a particular order
      for bad_string, replacement in UNDESIRABLE_STRING_REPLACEMENTS:
          line = line.replace(bad_string, replacement)
  
      for bad_char, replacement in iteritems(UNDESIRABLE_CHAR_REPLACEMENTS):
          line = line.replace(bad_char, replacement)
  
      return line
docs: Replace certain bad characters in a text line.
      @param line: (string) the text line in which bad characters are to
                   be replaced.
      @return: (string) the text line after the bad characters have been
                        replaced.