def is_boolean(value):
    """:yaql:isBoolean

    Returns true if value is boolean, otherwise false.

    :signature: isBoolean(value)
    :arg value: value to check
    :argType value: any
    :returnType: boolean

    .. code::

        yaql> isBoolean(false)
        true
        yaql> isBoolean(0)
        false
    """
    return isinstance(value, bool)