code: def _query_string_params(flask_request):
          
          query_string_dict = {}
  
          # Flask returns an ImmutableMultiDict so convert to a dictionary that becomes
          # a dict(str: list) then iterate over
          for query_string_key, query_string_list in flask_request.args.lists():
              query_string_value_length = len(query_string_list)
  
              # if the list is empty, default to empty string
              if not query_string_value_length:
                  query_string_dict[query_string_key] = ""
              else:
                  # APIGW doesn't handle duplicate query string keys, picking the last one in the list
                  query_string_dict[query_string_key] = query_string_list[-1]
  
          return query_string_dict
docs: Constructs an APIGW equivalent query string dictionary
  
          Parameters
          ----------
          flask_request request
              Request from Flask
  
          Returns dict (str: str)
          -------
              Empty dict if no query params where in the request otherwise returns a dictionary of key to value