'Does select on open connections.'

def _select(self):

    readable = [self.socket.handle.fileno(), self._read.fileno()]
    writable = []
    for (i, connection) in self.clients.items():
        if connection.is_readable():
            readable.append(connection.fileno())
        if connection.is_writeable():
            writable.append(connection.fileno())
        if connection.is_closed():
            del self.clients[i]
    return select.select(readable, writable, readable)
