When no value is given for an amount field, we do not want to fail with
an exception, as it is perfectly valid in camt files.
Instead we want to return nil to make it clear that there is noving
to convert into an integer or bigdecimal.
That also prevents hiding that the value is missing, as would be the
case in case of converting to 0/0.0
We cannot make an assumption about whether one needs to differentiate it
however, checking for nil is possible and default to 0.
If we already default to 0, that becomes impossible.
When no value is given for an amount field, we do not want to fail with an exception, as it is perfectly valid in camt files. Instead we want to return nil to make it clear that there is noving to convert into an integer or bigdecimal. That also prevents hiding that the value is missing, as would be the case in case of converting to 0/0.0 We cannot make an assumption about whether one needs to differentiate it however, checking for nil is possible and default to 0. If we already default to 0, that becomes impossible.
Refs #21