code: public <T> T getAsNullableType(Class<T> type, String key) {
  		Object value = getAsObject(key);
  		return TypeConverter.toNullableType(type, value);
  	}
docs: Converts map element into a value defined by specied typecode. If conversion
  is not possible it returns null.
  
  @param type the Class type that defined the type of the result
  @param key  a key of element to get.
  @return element value defined by the typecode or null if conversion is not
  supported.
  
  @see TypeConverter#toNullableType(Class, Object)