replace the following

// object arg = null;
if (arg1 == null) 
{
  throw new ArgumentNullException(nameof(arg1));
}
_arg1 = arg1;

with

// object arg = null;
_arg1 = arg.ThrowIfNull(nameof(arg));

replace the following

// object arg = null;
if (arg1 == null) 
{
  throw new ArgumentNullException(nameof(arg1), message);
}
_arg1 = arg1;

with

// object arg = null;
_arg1 = arg.ThrowIfNull(nameof(arg), message);

replace the following

// var arg = "";
if(string.IsNullOrEmpty(arg))
{
  throw new ArgumentNullException(nameof(arg));
}
_arg1 = arg1;

with

// var arg = "";
var _arg = arg.ThrowIfNullOrEmpty(nameof(arg)); // throws ArgumentNullException("arg");