How to use the lesscpy.lessc.utility.destring function in lesscpy

def isurl(self, string, *args):
        """Is url
        args:
            string (str): match
        returns:
            bool
        """
        arg = utility.destring(string)
        regex = re.compile(
            r'^(?:http|ftp)s?://'  # http:// or https://
            r'(?:(?:[A-Z0-9](?:[A-Z0-9-]{0,61}[A-Z0-9])?\.)+'
            r'(?:[A-Z]{2,6}\.?|[A-Z0-9-]{2,}\.?)|'  # domain...
            # localhost...
            r'localhost|'
            r'\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})'  # ...or ip
            # optional port
            r'(?::\d+)?'
            r'(?:/?|[/?]\S+)$',
            re.IGNORECASE)
        return regex.match(arg)

def swap(self, name):
        """ Swap variable name for variable value
        Args:
            name (str): Variable name
        Returns:
            Variable value (Mixed)
        """
        if name.startswith('@@'):
            var = self.variables(name[1:])
            if var is False:
                raise SyntaxError('Unknown variable %s' % name)
            name = '@' + utility.destring(var.value[0])
            var = self.variables(name)
            if var is False:
                raise SyntaxError('Unknown variable %s' % name)
        elif name.startswith('@{'):
            var = self.variables('@' + name[2:-1])
            if var is False:
                raise SyntaxError('Unknown escaped variable %s' % name)
            if isinstance(var.value[0], string_types):
                var.value[0] = utility.destring(var.value[0])
        else:
            var = self.variables(name)
            if var is False:
                raise SyntaxError('Unknown variable %s' % name)
        return var.value

Variable value (Mixed)
        """
        if name.startswith('@@'):
            var = self.variables(name[1:])
            if var is False:
                raise SyntaxError('Unknown variable %s' % name)
            name = '@' + utility.destring(var.value[0])
            var = self.variables(name)
            if var is False:
                raise SyntaxError('Unknown variable %s' % name)
        elif name.startswith('@{'):
            var = self.variables('@' + name[2:-1])
            if var is False:
                raise SyntaxError('Unknown escaped variable %s' % name)
            if isinstance(var.value[0], string_types):
                var.value[0] = utility.destring(var.value[0])
        else:
            var = self.variables(name)
            if var is False:
                raise SyntaxError('Unknown variable %s' % name)
        return var.value

def p_statement_import(self, p):
        """ import_statement     : css_import t_ws string t_semicolon
                                 | css_import t_ws css_string t_semicolon
                                 | css_import t_ws css_string media_query_list t_semicolon
                                 | css_import t_ws fcall t_semicolon
                                 | css_import t_ws fcall media_query_list t_semicolon
        """
        #import pdb; pdb.set_trace()
        if self.importlvl > 8:
            raise ImportError(
                'Recrusive import level too deep > 8 (circular import ?)')
        if isinstance(p[3], string_types):
            ipath = utility.destring(p[3])
        elif isinstance(p[3], list):
            p[3] = Import(p[3], p.lineno(4)).parse(self.scope)
            ipath = utility.destring(p[3])
        elif isinstance(p[3], Call):
            # NOTE(saschpe): Always in the form of 'url("...");', so parse it
            # and retrieve the inner css_string. This whole func is messy.
            p[3] = p[3].parse(
                self.scope)  # Store it as string, Statement.fmt expects it.
            ipath = utility.destring(p[3][4:-1])
        fn, fe = os.path.splitext(ipath)
        if not fe or fe.lower() == '.less':
            try:
                cpath = os.path.dirname(os.path.abspath(self.target))
                if not fe:
                    ipath += '.less'
                filename = "%s%s%s" % (cpath, os.sep, ipath)
                if os.path.exists(filename):
                    recurse = LessParser(
                        importlvl=self.importlvl + 1,

args:
            string (str): string to format
            args (list): format options
        returns:
            str
        """
        format = string
        items = []
        m = re.findall('(%[asdA])', format)
        if m and not args:
            raise SyntaxError('Not enough arguments...')
        i = 0
        for n in m:
            v = {
                '%A': urlquote,
                '%s': utility.destring,
            }.get(n, str)(args[i])
            items.append(v)
            i += 1
        format = format.replace('%A', '%s')
        format = format.replace('%d', '%s')
        return format % tuple(items)

def escape(self, string, *args):
        """Less Escape.
        args:
            string (str): string to escape
        returns:
            str
        """
        return utility.destring(string.strip('~'))