map objects c# with mapper

// map two objects
var a = new {a = 1, b = 2};
var b = new {a = 3, b = 4};
var c = a.MapWith(b);

// map array of objects
var a = new[] { new {a = 1, b = 2}, new {a = 3, b = 4} };
var b = new[] { new {a = 5, b = 6}, new {a = 7, b = 8} };
var c = a.MapWith(b);

// map list of objects
var a = new List<{a = 1, b = 2}> { new {a = 1, b = 2}, new {a = 3, b = 4} };
var b = new List<{a = 1, b = 2}> { new {a = 5, b = 6}, new {a = 7, b = 8} };
var c = a.MapWith(b);

// map any IEnumerable of objects
var a = new List<{a = 1, b = 2}> { new {a = 1,