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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 _parse_metadata_filename(self, metadata):
 """ Parse the header metadata to pull out the filename and then store it under the key 'filename' """

        index = metadata['Content-Disposition'].index('=')+1
        metadata['filename'] = metadata['Content-Disposition'][index:].replace('"', '')
        return metadata