code: function MapType(attrs, opts) {
    Type.call(this);
  
    if (!attrs.values) {
      throw new Error(f('missing map values: %j', attrs));
    }
    this._values = createType(attrs.values, opts);
  
    // Addition by Edwin Elia
    var keys = attrs.keys;
    if (!keys) {
      keys = 'string';
    }
    this._keys = createType(keys, opts);
  }
docs: Avro map.
  
  Represented as vanilla objects.