univocalic_davasaan bug?

I would like to give some feedback about the problem "univocalic_davasaan". My solution works well locally, but the site keeps telling me that the answer of my program is -1:

Your result: -1 Right result: 0 Fail: davasaan(1)

You can see locally the answer is really

y = (lambda x: 1+(x>0 and y(x-10)))

davasaan = lambda x: y(x)-2

davasaan(1)

0

From: http://www.checkio.org/mission/univocalic_davasaan/solve/

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