Helper function to build command line arguments out of dict.

def convert_kwargs_to_cmd_line_args(kwargs):
    """Helper function to build command line arguments out of dict."""
    args = []
    for k in sorted(kwargs.keys()):
        v = kwargs[k]
        args.append('-{}'.format(k))
        if v is not None:
            args.append('{}'.format(v))
    return args