Mustache-Java: How to get value in Map by key

I am using JMustache in Java.

I have Map variable in my Mustache template. How can I fetch a value at a particular key in the map, as we do in Java (map.get()).

I know how to iterate through keys and values of a Map in a template. But I want a solution without iteration so that I can evaluate an expression such as:

Data

{
    "cities": [
        {
            "Tokyo": {
                "overview": {
                    "population": "19000000",
                    "area": "450000"
                }
            }
        },
        {
            "Sydney": {
                "overview": {
                    "population": "4500000",
                    "area": "6250000"
                }
            }
        }
    ]
}

Template

"The population of Tokyo is: {{cities['Tokyo'].overview.population}}"