cattrs is an open source Python library for structuring and unstructuring data.
cattrs works best with attrs classes, dataclasses and the usual
Python collections, but other kinds of classes are supported by manually
registering converters.

Python has a rich set of powerful, easy to use, built-in data types
like dictionaries, lists and tuples. These data types are also the lingua franca
of most data serialization libraries, for formats like json, msgpack, cbor, yaml
or toml.

Data types like this, and mappings like dict s in particular, represent
unstructured data. Your data is, in all likelihood, structured:
not all combinations of field names or values are valid inputs to your programs.
In Python, structured data is better represented with classes and enumerations.
attrs is an excellent library for declaratively describing the structure
of your data, and validating it.

When you're handed unstructured data (by your network, file system, database...),
cattrs helps to convert this data into structured data. When you have to convert
your structured data into data types other libraries can handle, cattrs turns
your classes and enumerations into dictionaries, integers and strings.

• Grigory Ustinov

• python3-module-cattrs