'Return a list giving the parameters required by a query.'

def analyze(self):

    class MockBindings(dict, ):
        def __contains__(self, key):
            self[key] = None
            return True
    bindings = MockBindings()
    used = {}
    ancestor = self.ancestor
    if isinstance(ancestor, ParameterizedThing):
        ancestor = ancestor.resolve(bindings, used)
    filters = self.filters
    if (filters is not None):
        filters = filters.resolve(bindings, used)
    return sorted(used)
