public void AddBlog(BlogPost toAdd)
{
var checkForExistingPost = GetBlog(toAdd.BlogPostId);
if (checkForExistingPost != null)
{
throw new Exception("Blog Id already exists");
}
else
{
toAdd.BlogPostId = BlogPosts.Max(m => m.BlogPostId) + 1;
BlogPosts.Add(toAdd);
}
}