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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 iter_archive(self, resource):
 """Returns iterator over files within archive. **Important Note**: caller should read files as they are yielded. Reading out of order is slow. Args: resource: path to archive or `tfds.download.Resource`. Returns: Generator yielding tuple (path_within_archive, file_obj). """

    if isinstance(resource, six.string_types):
      resource = resource_lib.Resource(path=resource)
    return extractor.iter_archive(resource.path, resource.extract_method)