def METHOD_NAME(self):
    self._symbols_path = {}
    symbols = []
    if get_resource("symbols"):
        for root, _, files in os.walk(get_resource("symbols")):
            for filename in files:
                if filename.startswith('.'):
                    continue
                symbol_file = posixpath.normpath(os.path.relpath(os.path.join(root, filename), get_resource("symbols"))).replace('\\', '/')
                theme = posixpath.dirname(symbol_file).replace('/', '-').capitalize()
                if not theme:
                    continue
                symbol_id = ':/symbols/' + symbol_file
                symbols.append({'symbol_id': symbol_id,
                                'filename': filename,
                                'theme': theme,
                                'builtin': True})
                self._symbols_path[symbol_id] = os.path.join(root, filename)
    directory = self.symbols_path()
    if directory:
        for root, _, files in os.walk(directory):
            for filename in files:
                if filename.startswith('.'):
                    continue
                symbol_file = posixpath.normpath(os.path.relpath(os.path.join(root, filename), directory)).replace('\\', '/')
                symbols.append({'symbol_id': symbol_file,
                                'filename': filename,
                                'builtin': False,
                                'theme': "Custom symbols"})
                self._symbols_path[symbol_file] = os.path.join(root, filename)
    symbols.sort(key=lambda x: x["theme"])
    return symbols