add map insed map flutter code example
Example 1: flutter get key from map
String key = values.keys.elementAt(index);
Example 2: flutter create new map
Map<String, int> map1 = {'zero': 0, 'one': 1, 'two': 2};
Map map2 = {'zero': 0, 'I': 'one', 10: 'X'};
var map3 = {'zero': 0, 'I': 'one', 10: 'X'};