JSON -> CSV: JSON documents with top-level list element... What to list?

Created by: JontuKontar

Reference JSON code:

{
    "d": {
        "__type": "ThisIsATest.Something.Seller.Models.PriceResult",
        "PartPriceDescriptions": [{
            "PartNumber":"25834953",
            "Description":"GRILLE",
            "L":443.3300,
            "T":332.5000,
            "FL":"$443.33",
            "FT":"$332.50"
        },{
            "PartNumber":"2565956",
            "Description":"REGULATOR",
            "L":164.7600,
            "T":115.3300,
            "FL":"$164.76",
            "FT":"$115.33"
        }],
        "QuoteId": "430663",
        "Errors": null,
        "TotalPrice": "$400.19"
    }
}

Command Used:

in2csv -f json -v [JSON Document]

Error Code Short:

Only JSON documents with a top-level list element are able to be converted (or a top-level dictionary if specified.

Error Code Long (-v):

Traceback (most recent call last):
  File "/usr/local/bin/in2csv", line 9, in <module>
    load_entry_point('csvkit==0.9.0', 'console_scripts', 'in2csv')()
  File "/Library/Python/2.7/site-packages/csvkit/utilities/in2csv.py", line 82, in launch_new_instance
    utility.main()
  File "/Library/Python/2.7/site-packages/csvkit/utilities/in2csv.py", line 76, in main
    data = convert.convert(self.input_file, filetype, **kwargs)
  File "/Library/Python/2.7/site-packages/csvkit/convert/__init__.py", line 40, in convert
    return json2csv(f, key, **kwargs)
  File "/Library/Python/2.7/site-packages/csvkit/convert/js.py", line 45, in json2csv
    raise TypeError('When converting a JSON document with a top-level dictionary element, a key must be specified.')
TypeError: When converting a JSON document with a top-level dictionary element, a key must be specified.

Question/Issue:

Thus far, I have tried almost everything except whatever this error code is looking for and I'm running out of possibilities to try. I have attempted to use -k d, -k d/PartPriceDescriptions, and a variety of others with no success. The error code is very terse and the supplementary documentation isn't much more detailed about the solutions for this particular error. What should I be doing?

FYI: In the end, I'm looking to return PartNumber: ,Description:, L & T, to be returned in the CSV file.