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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 _validate(self, writing=False):
 """Validate internal correctness."""

        if (((len(self.fragment_offset) != len(self.fragment_length)) or
             (len(self.fragment_length) != len(self.data_reference)))):
            msg = ("The lengths of the fragment offsets ({len_offsets}), "
                   "fragment lengths ({len_fragments}), and "
                   "data reference items ({len_drefs}) must be the same.")
            msg = msg.format(len_offsets=len(self.fragment_offset),
                             len_fragments=len(self.fragment_length),
                             len_drefs=len(self.data_reference))
            self._dispatch_validation_error(msg, writing=writing)
        if any([x <= 0 for x in self.fragment_offset]):
            msg = "Fragment offsets must all be positive."
            self._dispatch_validation_error(msg, writing=writing)
        if any([x <= 0 for x in self.fragment_length]):
            msg = "Fragment lengths must all be positive."
            self._dispatch_validation_error(msg, writing=writing)