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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 _logjacobian(self):
 """Calculates the logjacobian of the current parameters."""

        if self.sampling_transforms is None:
            logj = 0.
        else:
            logj = self.sampling_transforms.logjacobian(
                **self.current_params)
        return logj