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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 posterior_to_xarray(self):
 """Convert posterior samples to xarray."""

        data = self.posterior
        if not isinstance(data, dict):
            raise TypeError("DictConverter.posterior is not a dictionary")

        if "log_likelihood" in data:
            warnings.warn(
                "log_likelihood found in posterior."
                " For stats functions log_likelihood needs to be in sample_stats.",
                SyntaxWarning,
            )

        return dict_to_dataset(data, library=None, coords=self.coords, dims=self.dims)