Does F# have Seq.Single: seq<'a> -> 'a? [duplicate]

Question

Possible Duplicate:
F# equivalent of LINQ Single

This function should return the first element of the sequence if it's the only one, otherwise it throws exception.

Does F# have this as built-in function? If not, why is it? Seems C# has a similar one in Enumerable class extension functions.

Answer 1

Seq.exactlyOne ?