code: def _format_metadata_url(self, api_key, page_number):
      query_params = [
          ("command", "returnTicker"),
      ]
  
      return self._format_polo_query(query_params)
  
file_path: catalyst/catalyst/data/bundles/poloniex.py
imports: import sys
  from six.moves.urllib.parse import urlencode
  import pandas
  from catalyst.data.bundles.core import register_bundle
  from catalyst.data.bundles.base_pricing import BaseCryptoPricingBundle
  from catalyst.utils.memoize import lazyval
  from catalyst.curate.poloniex import PoloniexCurator
label_desc: Use image node_id 9 for calling the PoloniexBundle obj's underlying member method code with example usage: obj._format_metadata_url(api_key, page_number) and returns: self