Docker is on a rise, Terraform only allows flat maps or lists and generally the "Twelve-Factor App" manifest suggests storing configuration in environment variables, which are technically key-value pairs.
However, if you find yourself on a path of migrating your app towards twelve-factor, and for some reasons uses nested dictionaries/hashes as a configuration format, it can come in handy to have a standard library to interact with the two different representation formats of a key-value ENV variable list and the nested dict/hash representation.
This gist is meant to collect the different libraries or code snippets in different programming languages to interact with the two representation formats.
Python