code: def get_securities(self, page=1, **filter_param):
          
          url_path = self._build_url_path(None, None)
          params = {'page': page}
          # the endpoints respond just fine to invaliid query params,
          # they just ignore them, but the the real value of the endpoints
          # is only revealed when using the filters, so let's not waste
          # requests on filters that don't do anything.
          if filter_param:
              query_filter = filter_param.popitem()
              if query_filter[0] in self.VALID_SECURITY_FILTERS:
                  params[query_filter[0]] = query_filter[1]
              else:
                  error_msg = 'Invalid filter param. Must be one of: {0}'.format(','.join(self.VALID_SECURITY_FILTERS))
                  raise exceptions.PyChartsRequestException(error_msg)
  
          return self._get_data(url_path, params)
docs: Queries /<security_type> endpoint to return a paged
          list of securities.