def METHOD_NAME(self, log_group_name, log_stream_name_prefix=None, next_token=None):
    """Return a list of log streams in the given log group, filtered by the given prefix."""
    kwargs = {"logGroupName": log_group_name}
    if log_stream_name_prefix:
        kwargs["logStreamNamePrefix"] = log_stream_name_prefix
    if next_token:
        kwargs["nextToken"] = next_token
    return self._client.METHOD_NAME(**kwargs)