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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 int_bytes(cls, string):
        '''Convert string describing size to int.'''
        if string[-1] in ('k', 'm'):
            value = cls.int_0_inf(string[:-1])
            unit = string[-1]
            if unit == 'k':
                value *= 2 ** 10
            else:
                value *= 2 ** 20
            return value
        else:
            return cls.int_0_inf(string)