def argflatten(arg_list):
    """Some list arguments is actually a list of lists.
    A simple routine to faltten list of lists to a simple list

    Parameters
    ==========
    arg_list: list of lists
        Value of a list argument needs to be flatten

    Return
    ======
    arg_as_list: list
        The flattened list of lists

    """
    return [p for sublist in arg_list for p in sublist]