def from_binary(cls, pst, filename):
        """instantiate an parameter obsemble from a jco-type file

        Parameters
        ----------
        pst : pyemu.Pst
            a Pst instance
        filename : str
            the binary file name

        Returns
        -------
        pe : ParameterEnsemble

        """
        m = Matrix.from_binary(filename).to_dataframe()

        return ParameterEnsemble.from_dataframe(df=m, pst=pst)