corrupted json document for scraping

[pipermerriam]

What is wrong

While working on concurrency for scraping I hit a program crash. Now when I try to run the scraper this happens:

$ python __main__.py scrape
EthPM CLI v0.1.0a0

Traceback (most recent call last):
  File "__main__.py", line 126, in <module>
    main(parser, logger)
  File "__main__.py", line 115, in main
    scraper(args)
  File "__main__.py", line 43, in scraper
    last_scraped_block = trio.run(scrape, w3, ethpmcli_dir, start_block)
  File "/home/piper/python-environments/ethpm-cli/lib/python3.6/site-packages/trio/_core/_run.py", line 1444, in run
    raise runner.main_task_outcome.error
  File "/home/piper/projects/ethpm-cli/ethpm_cli/scraper.py", line 32, in scrape
    initialize_ethpm_dir(ethpm_dir, w3)
  File "/home/piper/projects/ethpm-cli/ethpm_cli/scraper.py", line 85, in initialize_ethpm_dir
    validate_chain_data_store(chain_data_path, w3)
  File "/home/piper/projects/ethpm-cli/ethpm_cli/validation.py", line 68, in validate_chain_data_store
    chain_data = json.loads(chain_data_path.read_text())
  File "/home/piper/.pyenv/versions/3.6.5/lib/python3.6/json/__init__.py", line 354, in loads
    return _default_decoder.decode(s)
  File "/home/piper/.pyenv/versions/3.6.5/lib/python3.6/json/decoder.py", line 342, in decode
    raise JSONDecodeError("Extra data", s, end)
json.decoder.JSONDecodeError: Extra data: line 26 column 2 (char 415)

The underlying JSON document is:

{
    "chain_id": "0x1",
    "scraped_blocks": [
        {
            "min": "0",
            "max": "295"
        },
        {
            "min": "297",
            "max": "297"
        },
        {
            "min": "302",
            "max": "303"
        },
        {
            "min": "309",
            "max": "309"
        },
        {
            "min": "313",
            "max": "313"
        }
    ]
}
 {
            "min": "313",
            "max": "313"
        }
    ]
}

Now this almost definitely from the file being written to by multiple concurrent threads, however, the program should gracefully handle corrupt files.