how to implement the cutomize button for facebbok and goolge in swift3 : Hi implement facebbok and google button but i cant set the corner radious for the button  here is my code 

        @IBOutlet var fb_login_btn: FBSDKLoginButton! 
              fb_login_btn.layer.cornerRadius = 20
        @IBOutlet var google_login_btn: GIDSignInButton!
      google_login_btn.layer.cornerRadius = 20

 how can i customize the button in swift3 anyone help me to solve this issues 
Thanks in advance 