C# Online Compiler | .NET Fiddle

using System;

class Parent
{
  public void Method(int x)
  {
    Console.WriteLine("Parent's version of Method");
  }   
}
    
class Child : Parent
{
  public void Method(double y)
  {
    Console.WriteLine("Child's version of Method");
  }
}

public class Program
{
  public static void Main()
  {
    Child c = new Child();
    c.Method(10);
  }
}

Compilation error (line 43, col 32): 'DocumentService' does not implement interface member 'IDocumentService.CreateDocument(AuthContext, string)'
Compilation error (line 43, col 32): 'DocumentService' does not implement interface member 'IDocumentService.GetDocument(AuthContext, Guid)'
Compilation error (line 43, col 32): 'DocumentService' does not implement interface member 'IDocumentService.AllDocuments(AuthContext)'