When I try to compile the sample code it gives the following error

error: no matching function for call to 'RS485Class::RS485Class(HardwareSerial&, int, int, int, int)'
 RS485Class RS485(Serial2, ATOM_DTU_RS485_RX, ATOM_DTU_RS485_TX, -1, -1);

Which makes sense as I don't understand where the RS485Class is defined or how it is in the below code sample. Has anyone got this working?

#include <M5Atom.h>
#include <ArduinoModbus.h>
#include <ArduinoRS485.h>
#include "ATOM_DTU_NB.h"

const int numCoils            = 10;
const int numDiscreteInputs   = 10;
const int numHoldingRegisters = 10;
const int numInputRegisters   = 10;

RS485Class RS485(Serial2, ATOM_DTU_RS485_RX, ATOM_DTU_RS485_TX, -1, -1);