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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _number_of_rows(self, start=0, count=100, **kwargs):
 """Internal method to format the number of rows the EPA API returns."""

        first = str(start)
        last = str(start + count)
        string_format = ':'.join([first, last])
        return string_format