def flatten_string_list(arglist):
    """
    Assemble a list of string, such as for a subprocess call.
    Input should be a string or a list containing only
    strings or similar lists.
    Output will be a list containing only strings.
    """
    if isinstance(arglist, ("".__class__, u"".__class__)):
        return [arglist]
    return sum([flatten_string_list(x) for x in arglist], [])