<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def next(self):
        '''
        Return the next iteration by popping `chunk_size` from the left and
        appending `chunk_size` to the right if there's info on the file left
        to be read.
        '''
        if self.__buffered is None:
            # Use floor division to force multiplier to an integer
            multiplier = self.__max_in_mem // self.__chunk_size
            self.__buffered = ""
        else:
            multiplier = 1
            self.__buffered = self.__buffered[self.__chunk_size:]

        data = self.__file.read(self.__chunk_size * multiplier)
        # Data is a byte object in Python 3
        # Decode it in order to append to self.__buffered str later
        # Use the salt util in case it's already a string (Windows)
        data = salt.utils.stringutils.to_str(data)

        if not data:
            self.__file.close()
            raise StopIteration

        self.__buffered += data
        return self.__buffered