<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def st_mtime(self):
 """Return the modification time in seconds."""

        mtime = self._st_mtime_ns / 1e9
        return mtime if self.use_float else int(mtime)