Accessing python dict using nested key lookup string

I am looking to create a simple nested "lookup" mechanism in python, and wanted to make sure there wasn't already something somewhere hidden in the vast libraries in python that doesn't already do this before creating it.

I am looking to take a dict that is formatted something like this

my_dict = { 
  "root": { 
    "secondary": { 
      "user1": { 
          "name": "jim", 
          "age": 24 
      }, 
      "user2": { 
        "name": "fred", 
        "age": 25 
      } 
    } 
  } 
}

and I am trying to have a way to access the data by using a decimal notation that would be something similar to

root.secondary.user2

and return that resulting dict back as a response. I am thinking that there must be something that does this and I could write one without much difficulty but I want to make sure I am not recreating something I might be missing from the documentation. Thanks