code: def get_total_supply(self) -> int:
          
          func = InvokeFunction('totalSupply')
          response = self.__sdk.get_network().send_neo_vm_transaction_pre_exec(self.__hex_contract_address, None, func)
          try:
              total_supply = ContractDataParser.to_int(response['Result'])
          except SDKException:
              total_supply = 0
          return total_supply
docs: This interface is used to call the TotalSupply method in ope4
          that return the total supply of the oep4 token.
  
          :return: the total supply of the oep4 token.