@_infer_type.register(irast.DistinctOp)
def __infer_distinctop(ir, schema):
    result = infer_type(ir.expr, schema)
    return result
@_infer_type.register(irast.DistinctOp)
def __infer_distinctop(ir, schema):
    result = infer_type(ir.expr, schema)
    return result