class ActivityHubException(Exception):
    """Basic exception for errors raised by TiOPS"""

    def __init__(self, msg=None):
        super(ActivityHubException, self).__init__(msg)


class ActivityValidationError(ActivityHubException, ValueError):
    """Value validation error for Activity Hub"""

    def __init__(self, msg=None):
        if not msg:
            msg = 'Validation failed for required fields.'
        super(ActivityValidationError, self).__init__(msg)


class ActivityQueryError(ActivityHubException, ValueError):
    """Query validation or processing error for Activity Hub"""

    def __init__(self, msg=None):
        if not msg:
            msg = 'Invalid query.'
        super(ActivityQueryError, self).__init__(msg)


class ActivityNotFoundError(ActivityHubException):
    """Query error indicating identity not found in Activity Hub"""

    def __init__(self, msg=None):
        if not msg:
            msg = 'Requested identity not found.'
        super(ActivityNotFoundError, self).__init__(msg)


class ActivityAuthenticationError(ActivityHubException):
    """Authentication validation failure for Activity Hub"""

    def __init__(self, msg=None):
        if not msg:
            msg = 'Authentication failure.'
        super(ActivityAuthenticationError, self).__init__(msg)