def flattenList(inList=None):
    """ Reduces a list of lists to a single 1-dimension list.
    Args:
        inList: candidate list
    Returns: 1-D list
    """
    flat_list = []
    if inList is not None and inList is not []:
        _ = [flat_list.extend(item) if isinstance(item, list) else flat_list.append(item) for item in inList if item]
    return flat_list