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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 download_data_impl(self, run, tag, response_format):
 """Provides a response for downloading scalars data for a data series. Args: run: The run. tag: The specific tag. response_format: A string. One of the values of the OutputFormat enum of the scalar plugin. Raises: ValueError: If the scalars plugin is not registered. Returns: 2 entities: - A JSON object response body. - A mime type (string) for the response. """

    scalars_plugin_instance = self._get_scalars_plugin()
    if not scalars_plugin_instance:
      raise ValueError(('Failed to respond to request for /download_data. '
                        'The scalars plugin is oddly not registered.'))

    body, mime_type = scalars_plugin_instance.scalars_impl(
        tag, run, None, response_format)
    return body, mime_type