# ask-community

Jordan Wolinsky

07/17/2023, 11:56 PM
Hey, ran into a weird error when using sensors, and optional inputs at the top level of a graph. The error linked below gets raised even tho an empty input should be valid. If the input to the graph is provided, the sensor works.
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from typing import Optional
from dagster import Nothing, PythonObjectDagsterType, RunRequest, graph, In, op, sensor
from pathlib import Path

DagsterConfigurablePathType = PythonObjectDagsterType(python_type=(Path, Nothing))

def no_op(foo: Optional[Path]) -> None:

@graph(ins={"foo": In(DagsterConfigurablePathType)})
def bar(foo: Optional[Path]) -> None:

job = bar.to_job(name="job")

def foobar_sensor():
    # Following fails due to an error thrown here.  This is on 1.2.7 so maybe it was fixed since then.
    # <>
    # DagsterConfigurablePathType.is_nothing evaluates to False
    # this is called downstream which causes the error to be raised.
    yield RunRequest(run_key="1", run_config={"inputs": {}})


07/18/2023, 8:50 PM
Hi Jordan. I think the error message can definitely be confusing here--jobs cannot have unconnected inputs, so when a graph is converted to a job, input values have to be passed in:
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job = bar.to_job(name="job", input_values={"foo": None})
Another option would be to specify these input values through config. Since you have a custom input type, you may have to define a default value on the input, and override those defaults via config.