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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_binary(self,filename):
 """write the parameter ensemble to a jco-style binary file Parameters filename : str the filename to write Returns ------- None Note ---- this function back-transforms inplace with respect to log10 before writing """


        retrans = False
        if self.istransformed:
            self._back_transform(inplace=True)
            retrans = True
        if self.isnull().values.any():
            warnings.warn("NaN in par ensemble",PyemuWarning)
        self.as_pyemu_matrix().to_coo(filename)
        if retrans:
            self._transform(inplace=True)