Steps to reproduce:

1. call the function specifing hostids="YYYYY" and (itemids=["XXXXX"] or itemids="XXXXXX" etc ) and filters in time
   In Example
   z.history.get(hostids=10350, itemids=46525, history=0, time_from=1538132400.0, time_till=1538136000.0, sortfield='clock', sortorder='ASC')

Result:

returns all the history values for all the items of the host

Expected:
just the history values for the item specified

Work arround:

specify the filter filter like

z.history.get(hostids=10350, itemids=46525, history=0, time_from=1538132400.0, time_till=1538136000.0, sortfield='clock', sortorder='ASC', filter={"itemid":"46525"})