code: def create_query(key, person, event=None, timestamp=None,
                   identity=None, properties=None):
      
      if properties is None:
          properties = {}
  
      query_dict = {KEY_KEY: key, PERSON_KEY: person}
      if timestamp:
          query_dict[TIME_FLAG_KEY] = 1
          query_dict[TIME_KEY] = int(timestamp)
      if event:
          query_dict[EVENT_NAME_KEY] = event
      if identity:
          query_dict[ALIAS_KEY] = identity
      query_dict.update(properties)
      return urlencode(query_dict)
docs: Build and encode query string.
  
      :param key: API key for product, found on the
                  "KISSmetrics Settings".
      :param person: individual performing `event`
      :param event: event name that was performed
      :param timestamp: when `event` was performed; optional for
                        back-dating
      :param identity: individual to alias to `person`
      :param properties: any additional data to include
      :type properties: dict
  
      :returns: URL encoded string representing query string
      :rtype: str
  
      .. note::
  
          When a ``timestamp`` is provided, the ``TIME_FLAG_KEY`` will
          be set to ``1`` and included.