parameters: (filename, lines, error)
docstring: Logs an error for each line containing bad characters.
  
    Two kinds of bad characters:
  
    1. Unicode replacement characters: These indicate that either the file
    contained invalid UTF-8 (likely) or Unicode replacement characters (which
    it shouldn't).  Note that it's possible for this to throw off line
    numbering if the invalid UTF-8 occurred adjacent to a newline.
  
    2. NUL bytes.  These are problematic for some tools.
  
    Args:
      filename: The name of the current file.
      lines: An array of strings, each representing a line of the file.
      error: The function to call with any errors found.
docstring_summary: Logs an error for each line containing bad characters.
docstring_tokens: Logs an error for each line containing bad characters .
function: def CheckForBadCharacters(filename, lines, error):
    """Logs an error for each line containing bad characters.
  
    Two kinds of bad characters:
  
    1. Unicode replacement characters: These indicate that either the file
    contained invalid UTF-8 (likely) or Unicode replacement characters (which
    it shouldn't).  Note that it's possible for this to throw off line
    numbering if the invalid UTF-8 occurred adjacent to a newline.
  
    2. NUL bytes.  These are problematic for some tools.
  
    Args:
      filename: The name of the current file.
      lines: An array of strings, each representing a line of the file.
      error: The function to call with any errors found.
    """
    for linenum, line in enumerate(lines):
      if unicode_escape_decode('\ufffd') in line:
        error(filename, linenum, 'readability/utf8', 5,
              'Line contains invalid UTF-8 (or Unicode replacement character).')
      if '\0' in line:
        error(filename, linenum, 'readability/nul', 5, 'Line contains NUL byte.')
function_tokens: def CheckForBadCharacters ( filename , lines , error ) : for linenum , line in enumerate ( lines ) : if unicode_escape_decode ( '\ufffd' ) in line : error ( filename , linenum , 'readability/utf8' , 5 , 'Line contains invalid UTF-8 (or Unicode replacement character).' ) if '\0' in line : error ( filename , linenum , 'readability/nul' , 5 , 'Line contains NUL byte.' )