Sample of extension method in F#

F# ExtensionMethods

namespace ExtensionFSharp

module CollectionExtensions = 
   
    type System.Collections.Generic.IEnumerable<'a> with 
    member this.ForEach(f:'a -> unit) = 
        for item in this do 
        f item


open System.Linq 
open ExtensionFSharp.CollectionExtensions

let range = {1 .. 10}  
range.ForEach(fun i -> printfn "%i" i)