From their methodology section:
> The data include responses only from the official Python Software Foundation channels. After filtering out duplicate and non-reliable responses, the data-set includes more than 18,000 responses collected in October and November of 2018 via promoting the survey on python.org, the PSF blog, the PSF’s Twitter and LinkedIn accounts, official Python mailing lists, and Python-related subreddits. No product-, service-, or vendor-related channels were used, in order to prevent the survey from being slanted in favor of any specific tool or technology.