def word_before_after(a, sep):
    """
    returns word before and after :sep: in string :a:
    """
    word_before, word_after = "", ""
    if sep in a:
        word_before = a.split(str(sep))[0].strip().split(" ")[-1]
        word_after = a.split(str(sep))[1].strip().split(" ")[0]
    return word_before, word_after