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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 _sector_and_sz_itr(self, elf, data_start):
 """Iterator which returns starting address and sector size"""

        for entry_start in itertools.count(data_start, self.FLASH_SECTORS_STRUCT_SIZE):
            data = elf.read(entry_start, self.FLASH_SECTORS_STRUCT_SIZE)
            size, start = struct.unpack(self.FLASH_SECTORS_STRUCT, data)
            start_and_size = start, size
            if start_and_size == (self.SECTOR_END, self.SECTOR_END):
                return
            yield start_and_size