def splitInputString(input):
    """Split on comma and/or space.

    Parameters
    ----------
    input: str
        One or more values (e.g. file names), separated by a comma and/or
        a space.

    Returns
    -------
    words: list of strings
    """
    if isinstance(input, str):
        if input.strip() == '':
            words = ['']
        else:
            temp_words = input.split(',')
            words = []
            for word in temp_words:
                word = word.strip()
                if word == '':
                    words.append('')
                else:
                    words.extend(word.split())
    else:
        words = input
    return words
