code: public void addValueToIn(Object value, String name, Map<String, Object> map) {
          Object val = getValue(map, name);
           if (val instanceof Collection) {
               Object cleanValue = getCleanValue(value);
               ((Collection) val).add(cleanValue);
           } else if (val == null) {
               setValueForIn(value, name + "[0]", map);
           } else {
              throw new SlimFixtureException(false, "name is not a list but: " + val.getClass().getSimpleName());
           }
      }
docs: Adds a value to the end of a list.
  @param value value to be passed.
  @param name name to use this value for.
  @param map map to store value in.