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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 to_netcdf(self, filename, compress=True):
 """Write InferenceData to file using netcdf4. Parameters filename : str Location to write to compress : bool Whether to compress result. Note this saves disk space, but may make saving and loading somewhat slower (default: True). Returns ------- str Location of netcdf file """

        mode = "w"  # overwrite first, then append
        if self._groups:  # check's whether a group is present or not.
            for group in self._groups:
                data = getattr(self, group)
                kwargs = {}
                if compress:
                    kwargs["encoding"] = {var_name: {"zlib": True} for var_name in data.variables}
                data.to_netcdf(filename, mode=mode, group=group, **kwargs)
                data.close()
                mode = "a"
        else:  # creates a netcdf file for an empty InferenceData object.
            empty_netcdf_file = nc.Dataset(filename, mode="w", format="NETCDF4")
            empty_netcdf_file.close()
        return filename