dry-python ecosystem¶

from classes import typeclass
from returns.result import Result

@typeclass
def result_to_str(instance) -> str:
    """This is a typeclass definition to convert Result container to str."""

@result_to_str.instance(Result.success_type)
def _result_to_str_success(instance: Result) -> str:
    """The sad part is that we cannot make this case generic..."""
    return str(instance.unwrap())  # will always receive `Success` types

@result_to_str.instance(Result.failure_type)
def _result_to_str_failure(instance: Result) -> str:
    """But we can still use cases to work with top-level types!"""
    return str(instance.failure())  # will always receive `Failure` types