DB<105> map +{+2 => $_}, 1..3 # +2 IS A HASH KEY
 => ({ 2 => 1 }, { 2 => 2 }, { 2 => 3 })

  DB<106> map +{+2 , $_}, 1..3  # +2 IS A HASH KEY even without =>
 => ({ 2 => 1 }, { 2 => 2 }, { 2 => 3 })