Convert StackFrame object to json format.

def format_stack_frame_json(self):
        """Convert StackFrame object to json format."""
        stack_frame_json = {}
        stack_frame_json['function_name'] = get_truncatable_str(
            self.func_name)
        stack_frame_json['original_function_name'] = get_truncatable_str(
            self.original_func_name)
        stack_frame_json['file_name'] = get_truncatable_str(self.file_name)
        stack_frame_json['line_number'] = self.line_num
        stack_frame_json['column_number'] = self.col_num
        stack_frame_json['load_module'] = {
            'module': get_truncatable_str(self.load_module),
            'build_id': get_truncatable_str(self.build_id),
        }
        stack_frame_json['source_version'] = get_truncatable_str(
            self.source_version)

        return stack_frame_json