code: @NonNull
      @Override
      public MutableDocument setValue(@NonNull String key, Object value) {
          ((MutableDictionary) internalDict).setValue(key, value);
          return this;
      }
docs: Set an object value by key. Allowed value types are List, Date, Map, Number, null, String,
  Array, Blob, and Dictionary. The List and Map must contain only the above types.
  An Date object will be converted to an ISO-8601 format string.
  
  @param key   the key.
  @param value the Object value.
  @return this Document instance