__all__ = [
    "InvalidReactionException",
    "NoEnvironment",
    "NoUnobservablesException",
    "SensorNotAvailableException",
]


class InvalidReactionException(Exception):
    """
    Raised when a supplied reaction is invalid."""

    def __init__(self, msg="The supplied reaction is invalid."):
        Exception.__init__(self, msg)


class NoEnvironment(Exception):
    """"""

    def __init__(self, msg="No environment available."):
        Exception.__init__(self, msg)


class NoUnobservablesException(Exception):
    """"""

    def __init__(self, msg="Unoberservables not available."):
        Exception.__init__(self, msg)


class SensorNotAvailableException(Exception):
    """"""

    def __init__(self, msg="Sensor not available."):
        Exception.__init__(self, msg)
