function _d(){
    for (var ix = 0;ix < arguments.length; ix++)
      if (arguments[ix] != null)
        return arguments[ix]
    return null
  }
function _d(){
    for (var ix = 0;ix < arguments.length; ix++)
      if (arguments[ix] != null)
        return arguments[ix]
    return null
  }
function _d ( ) { for ( var ix = 0 ; ix < arguments . length ; ix ++ ) if ( arguments [ ix ] != null ) return arguments [ ix ] return null }
_d(args...): initialization helper that returns first arg that isn't null
_d ( args ... ) : initialization helper that returns first arg that isn t null