class Builder {

    private KunaTrade target = new KunaTrade();

    public Builder withId(int id) {
      target.id = id;
      return this;
    }

    public Builder withSide(String side) {
      target.side = KunaSide.valueOfIgnoreCase(side);
      return this;
    }

    public Builder withPrice(BigDecimal price) {
      target.price = price;
      return this;
    }

    public Builder withFunds(BigDecimal funds) {
      target.funds = funds;
      return this;
    }

    public Builder withMarket(String market) {
      target.market = market;
      return this;
    }

    @JsonProperty(CREATED_AT)
    public Builder withCreatedAt(String createdAt) {<FILL_FUNCTION_BODY>}

    public Builder withVolume(BigDecimal volume) {
      target.volume = volume;
      return this;
    }

    public KunaTrade build() {
      return this.target;
    }
  }

      if (createdAt == null || createdAt.isEmpty()) {
        target.createdAt = null;
      } else {
        target.createdAt = KunaUtils.toDate(createdAt);
      }
      return this;
    
<no_super_class>