List of account values for the given account,
        or of all accounts if account is left blank.

        This method is blocking on first run, non-blocking after that.

        Args:
            account: If specified, filter for this account name.

def accountSummary(self, account: str = '') -> List[AccountValue]:
        """
        List of account values for the given account,
        or of all accounts if account is left blank.

        This method is blocking on first run, non-blocking after that.

        Args:
            account: If specified, filter for this account name.
        """
        if not self.wrapper.acctSummary:
            # loaded on demand since it takes ca. 250 ms
            self.reqAccountSummary()
        if account:
            return [v for v in self.wrapper.acctSummary.values()
                    if v.account == account]
        else:
            return list(self.wrapper.acctSummary.values())