'Create dataset from first sheet.'

def create_dataset(self, in_stream):

    assert XLS_IMPORT
    xls_book = xlrd.open_workbook(file_contents=in_stream)
    dataset = tablib.Dataset()
    sheet = xls_book.sheets()[0]
    dataset.headers = sheet.row_values(0)
    for i in moves.range(1, sheet.nrows):
        dataset.append(sheet.row_values(i))
    return dataset
