Handle errors

Zettle shows any errors that occur during an operation to the user.
The error returned in the completion operation block is only intended for you as developers. For example, the iZettleSDKOperationCompletion and IZSDKPayPalQRCCompletion completion operation blocks. The object provides detailed information useful for debugging, diagnostics and logging. Make sure that you don't show errors that are returned in this block to the user.
For more information about the iZettleSDKOperationCompletion, IZSDKManualCardEntryCompletion and IZSDKPayPalQRCCompletion completion operation blocks, see iZettleSDKOperationCompletion, IZSDKManualCardEntryCompletion and IZSDKPayPalQRCCompletion respectively.