def _retry(self, context, backoff):
        '''
        A function which determines whether and how to retry.

        :param ~azure.storage.models.RetryContext context: 
            The retry context. This contains the request, response, and other data 
            which can be used to determine whether or not to retry.
        :param function() backoff:
            A function which returns the backoff time if a retry is to be performed.
        :return: 
            An integer indicating how long to wait before retrying the request, 
            or None to indicate no retry should be performed.
        :rtype: int or None
        '''
        # If the context does not contain a count parameter, this request has not 
        # been retried yet. Add the count parameter to track the number of retries.
        if not hasattr(context, 'count'):
            context.count = 0

        # Determine whether to retry, and if so increment the count, modify the 
        # request as desired, and return the backoff.
        if self._should_retry(context):
            context.count += 1
            
            # If retry to secondary is enabled, attempt to change the host if the 
            # request allows it
            if self.retry_to_secondary:
                self._set_next_host_location(context)

            return backoff(context)

        return None
def _retry ( self , context , backoff ) : if not hasattr ( context , 'count' ) : context . count = 0 if self . _should_retry ( context ) : context . count += 1 if self . retry_to_secondary : self . _set_next_host_location ( context ) return backoff ( context ) return None
A function which determines whether and how to retry.

        :param ~azure.storage.models.RetryContext context: 
            The retry context. This contains the request, response, and other data 
            which can be used to determine whether or not to retry.
        :param function() backoff:
            A function which returns the backoff time if a retry is to be performed.
        :return: 
            An integer indicating how long to wait before retrying the request, 
            or None to indicate no retry should be performed.
        :rtype: int or None