<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _get_endpoint(self, sub_domain):
 """ Get endpoint information from storage parameters. Update system with endpoint information and return information required to define roots. Args: self (pycosio._core.io_system.SystemBase subclass):
 System. sub_domain (str):
 Azure storage sub-domain. Returns: tuple of str: account_name, endpoint_suffix """

        storage_parameters = self._storage_parameters or dict()
        account_name = storage_parameters.get('account_name')

        if not account_name:
            raise ValueError('"account_name" is required for Azure storage')

        suffix = storage_parameters.get(
            'endpoint_suffix', 'core.windows.net')

        self._endpoint = 'http%s://%s.%s.%s' % (
            '' if self._unsecure else 's', account_name, sub_domain, suffix)

        return account_name, suffix.replace('.', r'\.')