def get_placeholder_formats_list(self, format_string):
        """
        Parses the format_string and returns a list of tuples
        (placeholder, format).
        """
        placeholders = []
        # Tokenize the format string and process them
        for token in self.tokens(format_string):
            if token.group("placeholder"):
                placeholders.append((token.group("key"), token.group("format")))
        return placeholders

        Parses the format_string and returns a list of tuples
        (placeholder, format).
        
py3status/formatter.py