The reformatted version of the class

Class1.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace MessyClassLibrary
{
    public class Class1
    {
        public Class1()
        {
        }

        public string GetFullName(string firstName,
                                  string lastName)
        {
            return $"{firstName} {lastName}";
        }
    }
}