def get_word_from_derewo_line(line):
    """Processor for individual line from DeReWo textfile.

    Args:
        line: Single line from DeReWo text file

    Returns:
        Lowercase word, None if invalid
    """
    line = line.split()

    # skip words with whitespace
    if len(line) > 2:
        return None

    # disregard DeReWo integer for frequency, only word is needed
    word = line[0]

    # lowercase passwords are good enough with sufficient word list length
    return word.lower()