Type Mismatch Error solution?

Data-Driven test using Excel as a data source.

Test Case: Updating a street address.

Street Address 1 is required. 

Street Address 2 is optional.

Implementation:

A Keyword Test accesses an Excel sheet and passes the cell values as parameters to keyword tests (UpdateStreetAddress1 and UpdateStreetAddress2).

Since Street Address 2 is optional, my first attempt was to leave Street Address 2 empty in the Excel sheet.  This triggers a Type Mismatch when UpdateStreetAddress2 is called as it is expecting a String.

My solution:

The calling Keyword Test would use aqConvert.VartoStr to essentially “type” the value when calling UpdateStreetAddress2.  This works and it would allow me to use aqConvert.VartoInt and/or aqConvert.VartoFloat as appropriate for other datatypes.

This seems to me the most straightforward approach, but I'm still learning test complete and perhaps there is a better solution.

Comments?