Not possible to specify more than one multiselect value in ObjectWidget URL parameters

[kkthxbye-code]

NetBox version

v3.5.0-beta2

Python version

3.8

Steps to Reproduce

1. Create a new ObjectWidget list with the Model "DCIM > Device".
2. In the URL parameters filter by two different location_id's:

{
    "location_id": 1,
    "location_id": 2
}

3. Save the widget

Expected Behavior

Widget should show devices belonging to either location with the id of 1 or 2.

Observed Behavior

Devices with location id 2 are shown. As the filters are passed as a JSON field and converted to a dict, it's not possible to have two entries with the same key. This is at odds with how the URL parameters are handled for multiselect fields, here the URL parameters would look like so:

?location_id=1&location_id=2

Passing the url parameters as a list also does not work:

{
    "location_id": [1,2]
}

This cause of the issue is similar to #12270. I believe setting doseq=True when calling urlencode would allow the above syntax to work, that is passing a list of values for the key with multiple values.

[jeremystretch]

This has been fixed by adding doseq=True as suggested, but I wanted to also highlight that this is the correct format for the arguments:

{
    "location_id": [1, 2]
}