<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def read_chunked(self):
 """Return iterator over container fragments of data source"""

        self._load_metadata()
        for i in range(self.npartitions):
            yield self._get_partition(i)