%isValid()

Aliases%isValid( ), %isValid( )
Parametersmixed @entity

    Returns 1 if the given entity is valid, otherwise returns 0. More
specifically the object is considered invalid if it is a string and
matches any of "none", "nobody", "nothing", "*ERR*", "-1". It is also
considered invalid if it is the null value or if it an entity pointer for
which the target entity is no longer in existence.