[ibkr_converter] `_check_forex_header` apparently doesn't check anything

[earshinov]

# 1

https://github.com/stadlmax/pyFIFOtax/blob/b0a828ba6419e196f712a51e038c5dbec3bb3f18/ibkr_converter.py#L65

As far as I can understand, the execution never goes past this line because _check_forex_header is called only from _process_forex, which has

if self.row[0] != "Trades" or self.row[3] != "Forex":

condition at the top, which is False for the header row as self.row[3] for the header row is "Asset Category", not "Forex"

# 2

~~If _check_forex_header actually checked anything, it would return an error for my IBKR statements which, for some reason, lacks the "Exchange" column in the "Trades" section.~~

Update: Nevermind, I didn't read the README carefully enough and used an Activity report instead of a Custom report.

[szotsaki]

PR merged, this issue is now fixed.