Format a SoSOptions object as a human or machine readable string.

            :param quote: quote option values
            :param sep: list separator string
            :param prefix: arbitrary prefix string
            :param suffix: arbitrary suffix string
            :param literal: print values as Python literals

def __str(self, quote=False, sep=" ", prefix="", suffix=""):
        """Format a SoSOptions object as a human or machine readable string.

            :param quote: quote option values
            :param sep: list separator string
            :param prefix: arbitrary prefix string
            :param suffix: arbitrary suffix string
            :param literal: print values as Python literals
        """
        args = prefix
        arg_fmt = "=%s"
        for arg in _arg_names:
            args += arg + arg_fmt + sep
        args.strip(sep)

        vals = [getattr(self, arg) for arg in _arg_names]
        if not quote:
            # Convert Python source notation for sequences into plain strings
            vals = [",".join(v) if _is_seq(v) else v for v in vals]
        else:
            def is_string(val):
                return isinstance(val, six.string_types)
            # Only quote strings if quote=False
            vals = ["'%s'" % v if is_string(v) else v for v in vals]

        return (args % tuple(vals)).strip(sep) + suffix