<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 async def load_credentials(self, credentials):
 """Load existing credentials."""

        split = credentials.split(':')
        self.identifier = split[0]
        self.srp.initialize(binascii.unhexlify(split[1]))
        _LOGGER.debug('Loaded AirPlay credentials: %s', credentials)