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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_file(self, filename):
 """ Write the ANTsImage to file Args ---- filename : string filepath to which the image will be written """

        filename = os.path.expanduser(filename)
        libfn = utils.get_lib_fn('toFile%s'%self._libsuffix)
        libfn(self.pointer, filename)