mnists/mnists/exceptions.py

class IntegrityError(Exception):
    def __init__(self, file, expected_hash, computed_hash):
        self.file = file
        self.expected_hash = expected_hash
        self.computed_hash = computed_hash

    def __str__(self):
        return """Failed to validate dataset: {self.file}
Hash mismatch: {self.computed_hash} should be {self.expected_hash}
Please check your local file for tampering or corruption.""".format(self=self)


class UnknownDatasetError(Exception):
    def __init__(self, dataset):
        self.dataset = dataset

    def __str__(self):
        return "Unknown mnist-like dataset: {self.dataset}".format(self=self)