code: def _get_balance(self, account_number):
          
          # Prepare data
          data = {"ctn": self.username,
                  "language": "en-US",
                  "accountNumber": account_number}
          # Http request
          try:
              raw_res = yield from self._session.post(BALANCE_URL,
                                                      data=data,
                                                      headers=self._headers,
                                                      timeout=self._timeout)
          except OSError:
              raise PyFidoError("Can not get balance")
          # Get balance
          try:
              json_content = yield from raw_res.json()
              balance_str = json_content\
                              .get("getAccountInfo", {})\
                              .get("balance")
          except (OSError, ValueError):
              raise PyFidoError("Can not get balance as json")
          if balance_str is None:
              raise PyFidoError("Can not get balance")
          # Casting to float
          try:
              balance = float(balance_str)
          except ValueError:
              raise PyFidoError("Can not get balance as float")
  
          return balance
docs: Get current balance from Fido.