def __call__(self, _connection):
		self._connections.append((self._uri, _connection))
		return _connection
If subunit is not installed, TestProtocolClient will be None, and
dataset/ETHPy150Open trendrr/whirlwind/whirlwind/contrib/sockjs/router_connection.py/connection.__call__--crossover with--dataset/ETHPy150Open twisted/twisted/twisted/trial/test/test_reporter.py/SubunitReporterNotInstalledTests.test_subunitNotInstalled