Extremely slow performance with getCellByPosition

The following code (in Python):

for r in range(dataRange.StartRow, dataRange.EndRow):
    for c in range(dataRange.StartColumn, dataRange.EndColumn):
        cell = sheet.getCellByPosition(c,r)


takes nearly two hours to run on a reasonably fast workstation for a
spreadsheet with 32 columns and ~27,000 rows (about .2 seconds per row). By
comparison, opening the file takes about 8 seconds and saving the file to a
CSV (which is functionally equivalent to the above) takes a few seconds. The
original file was written in Excel as an XLS (not XLSX). This seems
impossibly slow. Am I misusing the API somehow? What can I do to speed it
up?