Error when using summarize

[jtyr]

I'm trying to use summarize function and I'm getting a server error. The query is:

http://graphite:8888/render?target=summarize(derivative(collectd.host1.interface-eth0.if_errors.rx),%221min%22)

and that generates the following exception:

{"exception": "TypeError(\"unsupported operand type(s) for %: 'NoneType' and 'int'\",)", "event": "Exception"}
{"event": "Traceback (most recent call last):\n"}
{"event": "  File \"/usr/lib/python2.7/site-packages/flask/app.py\", line 1817, in wsgi_app\n    response = self.full_dispatch_request()\n"}
{"event": "  File \"/usr/lib/python2.7/site-packages/flask/app.py\", line 1477, in full_dispatch_request\n    rv = self.handle_user_exception(e)\n"}
{"event": "  File \"/usr/lib/python2.7/site-packages/flask/app.py\", line 1381, in handle_user_exception\n    reraise(exc_type, exc_value, tb)\n"}
{"event": "  File \"/usr/lib/python2.7/site-packages/flask/app.py\", line 1475, in full_dispatch_request\n    rv = self.dispatch_request()\n"}
{"event": "  File \"/usr/lib/python2.7/site-packages/flask/app.py\", line 1461, in dispatch_request\n    return self.view_functions[rule.endpoint](**req.view_args)\n"}
{"event": "  File \"/usr/lib/python2.7/site-packages/graphite_api/app.py\", line 394, in render\n    series_list = evaluateTarget(context, target)\n"}
{"event": "  File \"/usr/lib/python2.7/site-packages/graphite_api/app.py\", line 470, in evaluateTarget\n    result = evaluateTokens(requestContext, tokens)\n"}
{"event": "  File \"/usr/lib/python2.7/site-packages/graphite_api/app.py\", line 480, in evaluateTokens\n    return evaluateTokens(requestContext, tokens.expression)\n"}
{"event": "  File \"/usr/lib/python2.7/site-packages/graphite_api/app.py\", line 492, in evaluateTokens\n    return func(requestContext, *args, **kwargs)\n"}
{"event": "  File \"/usr/lib/python2.7/site-packages/graphite_api/functions.py\", line 2920, in summarize\n    bucketInterval = timestamp - (timestamp % interval)\n"}
{"event": "TypeError: unsupported operand type(s) for %: 'NoneType' and 'int'\n"}

Any idea what could be wrong?

[jtyr]

Actually, patch proposed by #88 fixed the problem.