def __init__(self, sheetname, ranges):

        self.sheetname = sheetname
        self.ranges = ranges
        self.bad_ranges = []

        letters = string.lowercase
        for range in self.ranges:
            row1, row2, col1, col2 = range
            col1 = letters[col1]
            col2 = letters[col2 - 1]
            row1 = row1 + 1
            self.bad_ranges.append(
                "{0}{1}:{2}{3}".format(col1, row1, col2, row2))
Concatenating a safe unicode string with another safe byte string or
dataset/ETHPy150Open tarbell-project/tarbell/tarbell/errors.py/MergedCellError.__init__--crossover with--dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.5/django/utils/safestring.py/SafeText.__add__