message: RM749 Make LEDGER_CARBON_TRACKER_ADDRESS .env parameter optional
diff: @@ -25,13 +25,13 @@ const assertEnv = (key: string): string => {
  return process.env[key] || '';
  }
  const contract_address = assertEnv('LEDGER_EMISSION_TOKEN_CONTRACT_ADDRESS')
  -const tracker_address = assertEnv('LEDGER_CARBON_TRACKER_ADDRESS')
  +const tracker_address = process.env['LEDGER_CARBON_TRACKER_ADDRESS']
  const network_name = assertEnv('LEDGER_ETH_NETWORK')
  const network_rpc_url = assertEnv('LEDGER_ETH_JSON_RPC_URL')
  const network_ws_url = process.env['LEDGER_ETH_WS_URL']
  export type OPTS_TYPE = {
  contract_address: string,
  - tracker_address: string,
  + tracker_address?: string,
  network_rpc_url: string,
  network_ws_url?: string,
  network_name: string,
  @@ -43,8 +43,6 @@ export type OPTS_TYPE = {
  export const OPTS: OPTS_TYPE = { contract_address, tracker_address, network_name, network_rpc_url, network_ws_url }
  -
  -
  // DB connector
  const db = PostgresDBService.getInstance()
  