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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 _pngmeta(self):
 """It will return GeoImage.tags as a PNG metadata object. Inspired by: public domain, Nick Galbreath http://blog.modp.com/2007/08/python-pil-and-png-metadata-take-2.html """

        reserved = ('interlace', 'gamma', 'dpi', 'transparency', 'aspect')

        try:
            tags = self.tags
        except AttributeError:
            tags = {}

        # Undocumented class
        from PIL import PngImagePlugin
        meta = PngImagePlugin.PngInfo()

        # Copy from tags to new dict
        for k__, v__ in tags.items():
            if k__ not in reserved:
                meta.add_text(k__, v__, 0)

        return meta