<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def GetStoredHostname(self):
 """Retrieves the stored hostname. The hostname is determined based on the preprocessing information that is stored inside the storage file. Returns: str: hostname. """

    store_number = len(self._hostnames)
    return self._hostnames.get(store_number, None)