_isContainedIn

Produces true if the received value is found in the specified List -- Function
Anything -> _isContainedIn (l, all) -> TrueOrFalse Type
Receives
A Value; if this a List or Set, the first element will be used. If Empty, this will always return False.
l
A List that might contain that Value.
all (optional)
If you set this to true, all of the values must be present; otherwise, it will return true if any are present.
Produces
True if that Value is found in the List; False otherwise
See _contains for the inverse of this function.