Trying to flatten deeply nested lists fails

[tillywoodfield]

Trying to flatten more than a 2-level nested list fails.

Version: 0.27.0

Steps to reproduce

Create example.json file containing a 3-level nested list:

{
  "main": [
    {
      "nested_list": [
        [
          ["a", "b"],
          ["c", "d"]
        ]
      ]
    }
  ]
}

Try to flatten:

flatten-tool flatten example.json

Result:

<class 'collections.OrderedDict'>
<class 'list'>
[['a', 'b'], ['c', 'd']]
'list' object has no attribute 'items'

Possible solutions

1. Flatten the whole list into a string, e.g. "[[[""a"",""b""],[""c"",""d""]]]", this is what flatterer does.
2. As a minimum, fail gracefully and ignore the list, allowing the rest of the process to continue.