Load the built-in functions into the scope.

def load_builtins(self):
        """Load the built-in functions into the scope."""
        for raw_name in dir(builtins):
            if not raw_name.startswith('__'):

                if raw_name.startswith('_'):
                    function_name = raw_name[1:]
                else:
                    function_name = raw_name

                builtin_function = FunctionSymbol(
                    Function(function_name, getattr(builtins, raw_name))
                )
                self.table[function_name] = builtin_function