/home/u5woRl/prog.fs(5,16): error FS0001: Type mismatch. Expecting a
'a -> bool
but given a
'a -> unit
The type 'bool' does not match the type 'unit'
/home/u5woRl/prog.fs(9,23): error FS0001: This expression was expected to have type
'a list
but here has type
string