class OCDSMergeError(Exception):
    """Base class for exceptions from within this package"""


class MissingDateKeyError(OCDSMergeError, KeyError):
    """Raised when a release is missing a 'date' key"""

    def __init__(self, key, message):
        self.key = key
        self.message = message

    def __str__(self):
        return str(self.message)


class NonObjectReleaseError(OCDSMergeError, TypeError):
    """Raised when a release is not an object"""


class NullDateValueError(OCDSMergeError, TypeError):
    """Raised when a release has a null 'date' value"""


class NonStringDateValueError(OCDSMergeError, TypeError):
    """Raised when a release has a non-string 'date' value"""


class InconsistentTypeError(OCDSMergeError, TypeError):
    """Raised when a path is a literal and an object in different releases"""


class OCDSMergeWarning(UserWarning):
    """Base class for warnings from within this package"""


class DuplicateIdValueWarning(OCDSMergeWarning):
    """Used when at least two objects in the same array have the same value for the 'id' field"""

    def __init__(self, path, id, message):
        self.path = path
        self.id = id
        self.message = message

    def __str__(self):
        return str(self.message)

[]