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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 _get_hash(self, file_obj):
 """ Compute hash for the `file_obj`. Attr: file_obj (obj):
 File-like object with ``.write()`` and ``.seek()``. Returns: str: Hexdigest of the hash. """

        size = 0
        hash_buider = self.hash_builder()
        for piece in self._get_file_iterator(file_obj):
            hash_buider.update(piece)
            size += len(piece)

        file_obj.seek(0)

        return "%s_%x" % (hash_buider.hexdigest(), size)